add subprocess, inspired by the Racket APIprocesses

17 files changed, 1387 insertions, 100 deletions

diff --git a/README.md b/README.md
index d6ef73c..e6cdfb1 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,8 @@
 * Full R7RS.
 * Libraries and programs work.
 * Native threads and some synchronization primitives.
+* [Proccess](Processes) is a subset of the [Racket](https://racket-lang.org/)
+[Processes API](https://docs.racket-lang.org/reference/subprocess.html).
 * Memory management featuring guardians and trackers. Guardians protect objects from being collected and trackers follow objects as they get moved by the copying part of the collector.
 * Full Unicode including reading and writing unicode characters to the console. Files in UTF-8 and UTF-16 encoding can be read and written.
 * The system is built around a compiler and VM. There is support for prompts and continuation marks.
@@ -25,11 +27,6 @@
 
 See [Foment](https://github.com/leftmike/foment/wiki/Foment) for more details.
 
-Future plans include
-* Providing line numbers and stack traces on errors.
-* R7RS large SRFIs.
-* composable continuations
-
 Please note that this is very much a work in progress. Please let me know if
 you find bugs and omissions. I will do my best to fix them.
 
diff --git a/src/base.scm b/src/base.scm
index 55f421d..afe5575 100644
--- a/src/base.scm
+++ b/src/base.scm
@@ -596,6 +596,20 @@
         lookup-type-tags
         comparator-context
         comparator-context-set!
+        subprocess
+        subprocess-wait
+        subprocess-status
+        subprocess-kill
+        subprocess-pid
+        subprocess?
+        system
+        system*
+        system/exit-code
+        system*/exit-code
+        process
+        process*
+        process/ports
+        process*/ports
         current-milliseconds
         time-apply
         time
@@ -944,6 +958,126 @@
                         (lambda () expr1 expr2 ...)
                         (lambda () (leave-exclusive exclusive))))))
 
+        (define (subprocess stdout stdin stderr command . args)
+            (apply values (apply %subprocess #f stdout stdin stderr command args)))
+
+        (define (shell-cmd/args cmd)
+            (cond-expand
+                (windows (list (get-environment-variable "ComSpec") (string-append "/c " cmd)))
+                (else (list "/bin/sh" "-c" cmd))))
+
+        (define (system cmd)
+            (apply system* (shell-cmd/args cmd)))
+
+        (define (system* cmd . args)
+            (= (apply system*/exit-code cmd args) 0))
+
+        (define (system/exit-code cmd)
+            (apply system*/exit-code (shell-cmd/args cmd)))
+
+        (define (system*/exit-code cmd . args)
+            (let* ((lst (apply process*/ports (current-output-port) (current-input-port)
+                        (current-error-port) cmd args))
+                    (ctrl (cadddr (cdr lst))))
+                (ctrl 'wait)
+                (ctrl 'exit-code)))
+
+        (define (process cmd)
+            (apply process*/ports (current-output-port) (current-input-port) (current-error-port)
+                    (shell-cmd/args cmd)))
+
+        (define (process* cmd . args)
+            (apply process*/ports (current-output-port) (current-input-port) (current-error-port)
+                    cmd args))
+
+        (define (process/ports out in err cmd)
+            (apply process*/ports out in err (shell-cmd/args cmd)))
+
+        (define (process-pipes out chldin in chldout err chlderr)
+          (if (or
+                  (and (output-port? out) (input-port? chldin))
+                  (and (input-port? in) (output-port? chldout))
+                  (and (output-port? err) (input-port? chlderr)))
+              (let ((lock (make-exclusive))
+                      (done (make-condition))
+                      (cnt 0))
+                  (if (and (output-port? out) (input-port? chldin))
+                      (run-thread
+                          (lambda ()
+                              (with-exclusive lock (set! cnt (+ cnt 1)))
+                              (%copy-port chldin out)
+                              (close-port chldin)
+                              (with-exclusive lock
+                                  (set! cnt (- cnt 1))
+                                  (if (= cnt 0)
+                                      (condition-wake done))))))
+                  (if (and (input-port? in) (output-port? chldout))
+                      (run-thread
+                          (lambda ()
+                              (with-exclusive lock (set! cnt (+ cnt 1)))
+                              (%copy-port in chldout)
+                              (close-port chldout)
+                              (with-exclusive lock
+                                  (set! cnt (- cnt 1))
+                                  (if (= cnt 0)
+                                      (condition-wake done))))))
+                  (if (and (output-port? err) (input-port? chlderr))
+                      (run-thread
+                          (lambda ()
+                              (with-exclusive lock (set! cnt (+ cnt 1)))
+                              (%copy-port chlderr err)
+                              (close-port chlderr)
+                              (with-exclusive lock
+                                  (set! cnt (- cnt 1))
+                                  (if (= cnt 0)
+                                      (condition-wake done))))))
+                  (lambda ()
+                      (define (wait)
+                          (if (= cnt 0)
+                              (leave-exclusive lock)
+                              (begin
+                                (condition-wait done lock)
+                                (wait))))
+                      (enter-exclusive lock)
+                      (wait)))
+              (lambda () #t)))
+
+        (define (process*/ports out in err cmd . args)
+            (let* ((ret (apply %subprocess #t out in err cmd args))
+                    (sub (car ret))
+                    (chldout (cadr ret))
+                    (chldin (caddr ret))
+                    (chlderr (cadddr ret))
+                    (pipes-wait (process-pipes out chldout in chldin err chlderr)))
+                (list
+                    (if out #f chldout)
+                    (if in #f chldin)
+                    (subprocess-pid sub)
+                    (if err #f chlderr)
+                    (lambda (what)
+                        (case what
+                            ((status)
+                                (let ((ret (subprocess-status sub)))
+                                    (if (integer? ret)
+                                        (if (zero? ret)
+                                            'done-ok
+                                            'done-error)
+                                        ret)))
+                            ((exit-code)
+                                (let ((ret (subprocess-status sub)))
+                                    (and (integer? ret) ret)))
+                            ((wait)
+                                (subprocess-wait sub)
+                                (pipes-wait))
+                            ((interrupt)
+                                (subprocess-kill sub #f))
+                            ((kill)
+                                (subprocess-kill sub #t))
+                            (else
+                                (full-error 'assertion-violation '<control-process> #f
+                        "<control-process>: expected status, exit-code, wait, interrupt, or kill"
+                                        what)))))))
+
         (define push-parameter (cons #f #f))
         (define pop-parameter (cons #f #f))
 
diff --git a/src/charset.cpp b/src/charset.cpp
index 36079fa..746e46a 100644
--- a/src/charset.cpp
+++ b/src/charset.cpp
@@ -495,8 +495,8 @@ Define("ucs-range->char-set", UCSRangeToCharSetPrimitive)(long_t argc, FObject a
     FixnumArgCheck("ucs-range->char-set", argv[0]);
     FixnumArgCheck("ucs-range->char-set", argv[1]);
 
-    FCh lower = AsFixnum(argv[0]);
-    FCh upper = AsFixnum(argv[1]);
+    FCh lower = (FCh) AsFixnum(argv[0]);
+    FCh upper = (FCh) AsFixnum(argv[1]);
     FObject base = EmptyCharSet;
 
     if (argc > 2)
diff --git a/src/foment.cpp b/src/foment.cpp
index b0a1428..8847d0c 100644
--- a/src/foment.cpp
+++ b/src/foment.cpp
@@ -99,7 +99,7 @@ void ErrorExitFoment(const char * what, const char * msg)
     {
         if (CheckHeapFlag || VerboseFlag)
             fprintf(stderr, "RandomSeed: " ULONG_FMT "\n", RandomSeed);
-        ExitFoment();
+        FlushStandardPorts();
     }
 
 #ifdef FOMENT_UNIX
@@ -1163,6 +1163,8 @@ FObject ThreadPPrimitiveFn(long_t argc, FObject argv[]);
 FObject ExclusivePPrimitiveFn(long_t argc, FObject argv[]);
 FObject ConditionPPrimitiveFn(long_t argc, FObject argv[]);
 FObject EphemeronPPrimitiveFn(long_t argc, FObject argv[]);
+FObject CharSetPPrimitiveFn(long_t argc, FObject argv[]);
+FObject SubprocessPPrimitiveFn(long_t argc, FObject argv[]);
 
 static FObject LookupTypeTags(FObject ttp)
 {
@@ -1208,6 +1210,10 @@ static FObject LookupTypeTags(FObject ttp)
             return(List(MakeFixnum(ConditionTag + INDIRECT_TAG_OFFSET)));
         else if (AsPrimitive(ttp)->PrimitiveFn == EphemeronPPrimitiveFn)
             return(List(MakeFixnum(EphemeronTag + INDIRECT_TAG_OFFSET)));
+        else if (AsPrimitive(ttp)->PrimitiveFn == CharSetPPrimitiveFn)
+            return(List(MakeFixnum(CharSetTag + INDIRECT_TAG_OFFSET)));
+        else if (AsPrimitive(ttp)->PrimitiveFn == SubprocessPPrimitiveFn)
+            return(List(MakeFixnum(SubprocessTag + INDIRECT_TAG_OFFSET)));
     }
 
     return(EmptyListObject);
@@ -1406,6 +1412,7 @@ FIndirectType IndirectTypes[] =
     {"builtin-type", WriteBuiltinType},
     {"builtin", WriteBuiltin},
     {"char-set", WriteCharSet},
+    {"subprocess", WriteSubprocess},
     {"free", 0}
 };
 
@@ -1511,6 +1518,7 @@ long_t SetupFoment(FThreadState * ts)
     SetupStrings();
     SetupVectors();
     SetupCharSets();
+    SetupProcess();
     SetupIO();
     SetupFileSys();
     SetupCompile();
diff --git a/src/foment.hpp b/src/foment.hpp
index be0ada4..fdcc8a0 100644
--- a/src/foment.hpp
+++ b/src/foment.hpp
@@ -225,6 +225,7 @@ typedef enum
     BuiltinTypeTag,
     BuiltinTag,
     CharSetTag,
+    SubprocessTag,
     FreeTag, // Only on Adult Generation
     BadDogTag // Invalid Tag
 } FIndirectTag;
@@ -543,11 +544,22 @@ typedef enum
     FromEnd
 } FPositionFrom;
 
+#ifdef FOMENT_WINDOWS
+typedef void * FFileHandle;
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+typedef long_t FFileHandle;
+#endif // FOMENT_UNIX
+
+#define INVALID_FILE_HANDLE ((FFileHandle) -1)
+
 typedef void (*FCloseInputFn)(FObject port);
 typedef void (*FCloseOutputFn)(FObject port);
 typedef void (*FFlushOutputFn)(FObject port);
 typedef int64_t (*FGetPositionFn)(FObject port);
 typedef void (*FSetPositionFn)(FObject port, int64_t pos, FPositionFrom frm);
+typedef FFileHandle (*FGetFileHandleFn)(FObject port);
 
 typedef struct
 {
@@ -560,6 +572,7 @@ typedef struct
     FFlushOutputFn FlushOutputFn;
     FGetPositionFn GetPositionFn;
     FSetPositionFn SetPositionFn;
+    FGetFileHandleFn GetFileHandleFn;
 } FGenericPort;
 
 #define AsGenericPort(obj) ((FGenericPort *) obj)
@@ -648,6 +661,8 @@ inline long_t PositioningPortP(FObject obj)
     return(AsGenericPort(obj)->Flags & PORT_FLAG_POSITIONING);
 }
 
+void FlushStandardPorts();
+
 // Binary and textual ports
 
 FObject HandOffPort(FObject port);
@@ -656,6 +671,7 @@ void CloseOutput(FObject port);
 void FlushOutput(FObject port);
 int64_t GetPosition(FObject port);
 void SetPosition(FObject port, int64_t pos, FPositionFrom frm);
+FFileHandle GetFileHandle(FObject port);
 
 // Binary ports
 
@@ -730,6 +746,10 @@ void WriteSimple(FObject port, FObject obj, long_t df);
 
 void WritePortObject(FWriteContext * wctx, FObject obj);
 
+// ---- Subprocesses ----
+
+void WriteSubprocess(FWriteContext * wctx, FObject obj);
+
 // ---- Pairs ----
 
 #define PairP(obj) (IndirectTag(obj) == PairTag)
@@ -1598,6 +1618,12 @@ inline void AtLeastFourArgsCheck(const char * who, long_t argc)
         RaiseExceptionC(Assertion, who, "expected at least four arguments", EmptyListObject);
 }
 
+inline void AtLeastFiveArgsCheck(const char * who, long_t argc)
+{
+    if (argc < 5)
+        RaiseExceptionC(Assertion, who, "expected at least five arguments", EmptyListObject);
+}
+
 inline void ZeroOrOneArgsCheck(const char * who, long_t argc)
 {
     if (argc > 1)
@@ -1923,7 +1949,6 @@ FObject ExecuteProc(FObject op);
 
 long_t SetupFoment(FThreadState * ts);
 extern ulong_t SetupComplete;
-void ExitFoment();
 void ErrorExitFoment(const char * what, const char * msg);
 
 // ---- Do Not Call Directly ----
@@ -1935,6 +1960,7 @@ void SetupCharacters();
 void SetupStrings();
 void SetupVectors();
 void SetupCharSets();
+void SetupProcess();
 void SetupHashTables();
 void SetupCompare();
 void SetupIO();
diff --git a/src/io.cpp b/src/io.cpp
index 3252683..b691328 100644
--- a/src/io.cpp
+++ b/src/io.cpp
@@ -66,9 +66,22 @@ FObject StandardError = NoValueObject;
 
 // ---- Binary Ports ----
 
+static FFileHandle InvalidFileHandle(FObject port)
+{
+    return(INVALID_FILE_HANDLE);
+}
+
+static FFileHandle GetObjectFileHandle(FObject port)
+{
+    FAssert(BinaryPortP(port) || TextualPortP(port));
+
+    return(GetFileHandle(AsGenericPort(port)->Object));
+}
+
 FObject MakeBinaryPort(FObject nam, FObject obj, void * ctx, FCloseInputFn cifn,
     FCloseOutputFn cofn, FFlushOutputFn fofn, FReadBytesFn rbfn, FByteReadyPFn brpfn,
-    FWriteBytesFn wbfn, FGetPositionFn gpfn, FSetPositionFn spfn)
+    FWriteBytesFn wbfn, FGetPositionFn gpfn, FSetPositionFn spfn,
+    FGetFileHandleFn gfhfn, ulong_t flgs)
 {
     FAssert((cifn == 0 && rbfn == 0 && brpfn == 0) || (cifn != 0 && rbfn != 0 && brpfn != 0));
     FAssert((cofn == 0 && wbfn == 0 && fofn == 0) || (cofn != 0 && wbfn != 0 && fofn != 0));
@@ -79,7 +92,8 @@ FObject MakeBinaryPort(FObject nam, FObject obj, void * ctx, FCloseInputFn cifn,
             "%make-binary-port");
     port->Generic.Flags = (cifn != 0 ? (PORT_FLAG_INPUT | PORT_FLAG_INPUT_OPEN) : 0)
             | (cofn != 0 ? (PORT_FLAG_OUTPUT | PORT_FLAG_OUTPUT_OPEN) : 0)
-            | (gpfn != 0 ? PORT_FLAG_POSITIONING : 0);
+            | (gpfn != 0 ? PORT_FLAG_POSITIONING : 0)
+            | flgs;
     port->Generic.Name = nam;
     port->Generic.Object = obj;
     port->Generic.Context = ctx;
@@ -88,6 +102,7 @@ FObject MakeBinaryPort(FObject nam, FObject obj, void * ctx, FCloseInputFn cifn,
     port->Generic.FlushOutputFn = fofn;
     port->Generic.GetPositionFn = gpfn;
     port->Generic.SetPositionFn = spfn;
+    port->Generic.GetFileHandleFn = gfhfn == 0 ? InvalidFileHandle : gfhfn;
     port->ReadBytesFn = rbfn;
     port->ByteReadyPFn = brpfn;
     port->WriteBytesFn = wbfn;
@@ -403,7 +418,7 @@ static FObject MakeBufferedPort(FObject port)
     }
 
     port = HandOffPort(port);
-    FObject nport = MakeBinaryPort(AsGenericPort(port)->Name, port, bc,
+    return(MakeBinaryPort(AsGenericPort(port)->Name, port, bc,
             InputPortOpenP(port) ? BufferedCloseInput : 0,
             OutputPortOpenP(port) ? BufferedCloseOutput : 0,
             OutputPortOpenP(port) ? BufferedFlushOutput : 0,
@@ -411,10 +426,9 @@ static FObject MakeBufferedPort(FObject port)
             InputPortOpenP(port) ? BufferedByteReadyP : 0,
             OutputPortOpenP(port) ? BufferedWriteBytes : 0,
             PositioningPortP(port) ? BufferedGetPosition : 0,
-            PositioningPortP(port) ? BufferedSetPosition : 0);
-    AsGenericPort(nport)->Flags |= PORT_FLAG_BUFFERED;
-
-    return(nport);
+            PositioningPortP(port) ? BufferedSetPosition : 0,
+            GetObjectFileHandle,
+            PORT_FLAG_BUFFERED));
 }
 
 static void SocketCloseInput(FObject port)
@@ -494,12 +508,9 @@ static void SocketWriteBytes(FObject port, void * b, ulong_t bl)
 
 static FObject MakeSocketPort(SOCKET s)
 {
-    FObject port = MakeBinaryPort(NoValueObject, NoValueObject, (void *) s, SocketCloseInput,
+    return(MakeBinaryPort(NoValueObject, NoValueObject, (void *) s, SocketCloseInput,
             SocketCloseOutput, SocketFlushOutput, SocketReadBytes, SocketByteReadyP,
-            SocketWriteBytes, 0, 0);
-    AsGenericPort(port)->Flags |= PORT_FLAG_SOCKET;
-
-    return(port);
+            SocketWriteBytes, 0, 0, 0, PORT_FLAG_SOCKET));
 }
 
 #ifdef FOMENT_WINDOWS
@@ -592,24 +603,31 @@ static void HandleSetPosition(FObject port, int64_t pos, FPositionFrom frm)
             frm == FromBegin ? FILE_BEGIN : (frm == FromCurrent ? FILE_CURRENT : FILE_END));
 }
 
+static FFileHandle HandleGetFileHandle(FObject port)
+{
+    FAssert(BinaryPortP(port) || TextualPortP(port));
+
+    return(AsGenericPort(port)->Context);
+}
+
 static FObject MakeHandleInputPort(FObject nam, HANDLE h)
 {
     if (GetFileType(h) == FILE_TYPE_PIPE)
         return(MakeBinaryPort(nam, NoValueObject, h, HandleCloseInput, 0, 0, HandleReadBytes,
-            PipeByteReadyP, 0, 0, 0));
+                PipeByteReadyP, 0, 0, 0, HandleGetFileHandle, 0));
 
     return(MakeBinaryPort(nam, NoValueObject, h, HandleCloseInput, 0, 0, HandleReadBytes,
-            FileByteReadyP, 0, HandleGetPosition, HandleSetPosition));
+            FileByteReadyP, 0, HandleGetPosition, HandleSetPosition, HandleGetFileHandle, 0));
 }
 
 static FObject MakeHandleOutputPort(FObject nam, HANDLE h)
 {
     if (GetFileType(h) == FILE_TYPE_PIPE)
         return(MakeBinaryPort(nam, NoValueObject, h, 0, HandleCloseOutput, HandleFlushOutput, 0, 0,
-                HandleWriteBytes, 0, 0));
+                HandleWriteBytes, 0, 0, HandleGetFileHandle, 0));
 
     return(MakeBinaryPort(nam, NoValueObject, h, 0, HandleCloseOutput, HandleFlushOutput, 0, 0,
-            HandleWriteBytes, HandleGetPosition, HandleSetPosition));
+            HandleWriteBytes, HandleGetPosition, HandleSetPosition, HandleGetFileHandle, 0));
 }
 #endif // FOMENT_WINDOWS
 
@@ -680,26 +698,34 @@ static int64_t FileDescGetPosition(FObject port)
     return(lseek((long_t) AsGenericPort(port)->Context, 0, SEEK_CUR));
 }
 
+static FFileHandle FileDescGetFileHandle(FObject port)
+{
+    FAssert(BinaryPortP(port) || TextualPortP(port));
+
+    return((FFileHandle) (AsGenericPort(port)->Context));
+}
+
 static void FileDescSetPosition(FObject port, int64_t pos, FPositionFrom frm)
 {
     FAssert(BinaryPortP(port) && PortOpenP(port) && PositioningPortP(port));
     FAssert(frm == FromBegin || frm == FromCurrent || frm == FromEnd);
 
-    lseek((long_t) AsGenericPort(port)->Context, pos, 
+    lseek((long_t) AsGenericPort(port)->Context, pos,
             frm == FromBegin ? SEEK_SET : (frm == FromCurrent ? SEEK_CUR : SEEK_END));
 }
 
 static FObject MakeFileDescInputPort(FObject nam, long_t fd)
 {
     return(MakeBinaryPort(nam, NoValueObject, (void *) fd, FileDescCloseInput, 0, 0,
-            FileDescReadBytes, FileDescByteReadyP, 0, FileDescGetPosition, FileDescSetPosition));
+            FileDescReadBytes, FileDescByteReadyP, 0, FileDescGetPosition, FileDescSetPosition,
+            FileDescGetFileHandle, 0));
 }
 
 static FObject MakeFileDescOutputPort(FObject nam, long_t fd)
 {
     return(MakeBinaryPort(nam, NoValueObject, (void *) fd, 0, FileDescCloseOutput,
             FileDescFlushOutput, 0, 0, FileDescWriteBytes, FileDescGetPosition,
-            FileDescSetPosition));
+            FileDescSetPosition, FileDescGetFileHandle, 0));
 }
 #endif // FOMENT_UNIX
 
@@ -744,7 +770,7 @@ static FObject MakeBytevectorInputPort(FObject bv)
     FAssert(BytevectorP(bv));
 
     return(MakeBinaryPort(NoValueObject, bv, 0, BvinCloseInput, 0, 0, BvinReadBytes,
-            BvinByteReadyP, 0, 0, 0));
+            BvinByteReadyP, 0, 0, 0, 0, 0));
 }
 
 static void BvoutCloseOutput(FObject port)
@@ -799,17 +825,16 @@ static FObject GetOutputBytevector(FObject port)
 
 static FObject MakeBytevectorOutputPort()
 {
-    FObject port = MakeBinaryPort(NoValueObject, EmptyListObject, 0, 0, BvoutCloseOutput,
-            BvoutFlushOutput, 0, 0, BvoutWriteBytes, 0, 0);
-    AsGenericPort(port)->Flags |= PORT_FLAG_BYTEVECTOR_OUTPUT;
-    return(port);
+    return(MakeBinaryPort(NoValueObject, EmptyListObject, 0, 0, BvoutCloseOutput,
+            BvoutFlushOutput, 0, 0, BvoutWriteBytes, 0, 0, 0, PORT_FLAG_BYTEVECTOR_OUTPUT));
 }
 
 // ---- Textual Ports ----
 
 FObject MakeTextualPort(FObject nam, FObject obj, void * ctx, FCloseInputFn cifn,
     FCloseOutputFn cofn, FFlushOutputFn fofn, FReadChFn rcfn, FCharReadyPFn crpfn,
-    FWriteStringFn wsfn, FGetPositionFn gpfn, FSetPositionFn spfn)
+    FWriteStringFn wsfn, FGetPositionFn gpfn, FSetPositionFn spfn, FGetFileHandleFn gfhfn,
+    ulong_t flgs)
 {
     FAssert((cifn == 0 && rcfn == 0 && crpfn == 0) || (cifn != 0 && rcfn != 0 && crpfn != 0));
     FAssert((cofn == 0 && wsfn == 0 && fofn == 0) || (cofn != 0 && wsfn != 0 && fofn != 0));
@@ -820,7 +845,8 @@ FObject MakeTextualPort(FObject nam, FObject obj, void * ctx, FCloseInputFn cifn
             "%make-textual-port");
     port->Generic.Flags = (cifn != 0 ? (PORT_FLAG_INPUT | PORT_FLAG_INPUT_OPEN) : 0)
             | (cofn != 0 ? (PORT_FLAG_OUTPUT | PORT_FLAG_OUTPUT_OPEN) : 0)
-            | (gpfn != 0 ? PORT_FLAG_POSITIONING : 0);
+            | (gpfn != 0 ? PORT_FLAG_POSITIONING : 0)
+            | flgs;
     port->Generic.Name = nam;
     port->Generic.Object = obj;
     port->Generic.Context = ctx;
@@ -829,6 +855,7 @@ FObject MakeTextualPort(FObject nam, FObject obj, void * ctx, FCloseInputFn cifn
     port->Generic.FlushOutputFn = fofn;
     port->Generic.GetPositionFn = gpfn;
     port->Generic.SetPositionFn = spfn;
+    port->Generic.GetFileHandleFn = gfhfn == 0 ? InvalidFileHandle : gfhfn;
     port->ReadChFn = rcfn;
     port->CharReadyPFn = crpfn;
     port->WriteStringFn = wsfn;
@@ -1099,6 +1126,13 @@ void SetPosition(FObject port, int64_t pos, FPositionFrom frm)
     AsGenericPort(port)->SetPositionFn(port, pos, frm);
 }
 
+FFileHandle GetFileHandle(FObject port)
+{
+    FAssert(BinaryPortP(port) || TextualPortP(port));
+
+    return(AsGenericPort(port)->GetFileHandleFn(port));
+}
+
 static void TranslatorCloseInput(FObject port)
 {
     FAssert(BinaryPortP(AsGenericPort(port)->Object));
@@ -1132,7 +1166,7 @@ static FObject MakeTranslatorPort(FObject port, FReadChFn rcfn, FCharReadyPFn cr
             OutputPortP(port) ? TranslatorFlushOutput : 0,
             InputPortP(port) ? rcfn : 0,
             InputPortP(port) ? crpfn : 0,
-            OutputPortP(port) ? wsfn : 0, 0, 0));
+            OutputPortP(port) ? wsfn : 0, 0, 0, GetObjectFileHandle, 0));
 }
 
 static ulong_t AsciiReadCh(FObject port, FCh * ch)
@@ -1497,6 +1531,32 @@ FObject OpenOutputFile(FObject fn)
     return(port);
 }
 
+FObject OpenInputPipe(FFileHandle fh)
+{
+#ifdef FOMENT_WINDOWS
+    return(MakeLatin1Port(MakeBufferedPort(
+            MakeHandleInputPort(MakeStringC("input-pipe"), fh))));
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+    return(MakeUtf8Port(MakeBufferedPort(
+            MakeFileDescInputPort(MakeStringC("input-pipe"), fh))));
+#endif // FOMENT_UNIX
+}
+
+FObject OpenOutputPipe(FFileHandle fh)
+{
+#ifdef FOMENT_WINDOWS
+    return(MakeLatin1Port(MakeBufferedPort(
+            MakeHandleOutputPort(MakeStringC("output-pipe"), fh))));
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+    return(MakeUtf8Port(MakeBufferedPort(
+            MakeFileDescOutputPort(MakeStringC("output-pipe"), fh))));
+#endif // FOMENT_UNIX
+}
+
 static void SinCloseInput(FObject port)
 {
     FAssert(TextualPortP(port));
@@ -1533,7 +1593,7 @@ FObject MakeStringInputPort(FObject s)
     FAssert(StringP(s));
 
     return(MakeTextualPort(NoValueObject, s, 0, SinCloseInput, 0, 0, SinReadCh, SinCharReadyP,
-            0, 0, 0));
+            0, 0, 0, 0, 0));
 }
 
 static void SoutCloseOutput(FObject port)
@@ -1588,10 +1648,8 @@ FObject GetOutputString(FObject port)
 
 FObject MakeStringOutputPort()
 {
-    FObject port = MakeTextualPort(NoValueObject, EmptyListObject, 0, 0, SoutCloseOutput,
-            SoutFlushOutput, 0, 0, SoutWriteString, 0, 0);
-    AsGenericPort(port)->Flags |= PORT_FLAG_STRING_OUTPUT;
-    return(port);
+    return(MakeTextualPort(NoValueObject, EmptyListObject, 0, 0, SoutCloseOutput,
+            SoutFlushOutput, 0, 0, SoutWriteString, 0, 0, 0, PORT_FLAG_STRING_OUTPUT));
 }
 
 static void CinCloseInput(FObject port)
@@ -1622,7 +1680,7 @@ static long_t CinCharReadyP(FObject port)
 FObject MakeStringCInputPort(const char * s)
 {
     return(MakeTextualPort(NoValueObject, NoValueObject, (void *) s, CinCloseInput, 0, 0,
-            CinReadCh, CinCharReadyP, 0, 0, 0));
+            CinReadCh, CinCharReadyP, 0, 0, 0, 0, 0));
 }
 
 // ---- Console Input and Output ----
@@ -2761,6 +2819,13 @@ static long_t ConCharReadyP(FObject port)
 }
 
 #ifdef FOMENT_WINDOWS
+static FFileHandle ConGetFileHandle(FObject port)
+{
+    FAssert(InputPortP(port) && ConsolePortP(port));
+
+    return(AsConsoleInput(port)->InputHandle);
+}
+
 static FObject MakeConsoleInputPort(FObject nam, HANDLE hin, HANDLE hout)
 {
     FConsoleInput * ci = MakeConsoleInput();
@@ -2771,8 +2836,7 @@ static FObject MakeConsoleInputPort(FObject nam, HANDLE hin, HANDLE hout)
     ci->OutputHandle = hout;
 
     FObject port = MakeTextualPort(nam, NoValueObject, ci, ConCloseInput, 0, 0, ConReadCh,
-            ConCharReadyP, 0, 0, 0);
-    AsGenericPort(port)->Flags |= PORT_FLAG_CONSOLE | PORT_FLAG_INTERACTIVE;
+            ConCharReadyP, 0, 0, 0, ConGetFileHandle, PORT_FLAG_CONSOLE | PORT_FLAG_INTERACTIVE);
     AsConsoleInput(port)->Mode = CONSOLE_INPUT_ECHO;
 
     return(port);
@@ -2806,15 +2870,19 @@ static void ConWriteString(FObject port, FCh * s, ulong_t sl)
 
 static FObject MakeConsoleOutputPort(FObject nam, HANDLE h)
 {
-    FObject port = MakeTextualPort(nam, NoValueObject, h, 0, ConCloseOutput, ConFlushOutput, 0,
-            0, ConWriteString, 0, 0);
-    AsGenericPort(port)->Flags |= PORT_FLAG_CONSOLE;
-
-    return(port);
+    return(MakeTextualPort(nam, NoValueObject, h, 0, ConCloseOutput, ConFlushOutput, 0,
+            0, ConWriteString, 0, 0, HandleGetFileHandle, PORT_FLAG_CONSOLE));
 }
 #endif // FOMENT_WINDOWS
 
 #ifdef FOMENT_UNIX
+static FFileHandle ConGetFileHandle(FObject port)
+{
+    FAssert(InputPortP(port) && ConsolePortP(port));
+
+    return(AsConsoleInput(port)->InputFd);
+}
+
 static FObject MakeConsoleInputPort(FObject nam, long_t ifd, long_t ofd, int fi)
 {
     FConsoleInput * ci = MakeConsoleInput();
@@ -2825,8 +2893,7 @@ static FObject MakeConsoleInputPort(FObject nam, long_t ifd, long_t ofd, int fi)
     ci->OutputFd = ofd;
 
     FObject port = MakeTextualPort(nam, NoValueObject, ci, ConCloseInput, 0, 0, ConReadCh,
-            ConCharReadyP, 0, 0, 0);
-    AsGenericPort(port)->Flags |= PORT_FLAG_CONSOLE;
+            ConCharReadyP, 0, 0, 0, ConGetFileHandle, PORT_FLAG_CONSOLE);
     if (fi)
     {
         AsGenericPort(port)->Flags |= PORT_FLAG_INTERACTIVE;
@@ -2862,11 +2929,8 @@ static void ConWriteString(FObject port, FCh * s, ulong_t sl)
 
 static FObject MakeConsoleOutputPort(FObject nam, long_t ofd)
 {
-    FObject port = MakeTextualPort(nam, NoValueObject, (void *) ofd, 0, ConCloseOutput,
-            ConFlushOutput, 0, 0, ConWriteString, 0, 0);
-    AsGenericPort(port)->Flags |= PORT_FLAG_CONSOLE;
-
-    return(port);
+    return(MakeTextualPort(nam, NoValueObject, (void *) ofd, 0, ConCloseOutput,
+            ConFlushOutput, 0, 0, ConWriteString, 0, 0, FileDescGetFileHandle, PORT_FLAG_CONSOLE));
 }
 #endif // FOMENT_UNIX
 
@@ -3189,6 +3253,44 @@ Define("set-port-position!", SetPortPositionPrimitive)(long_t argc, FObject argv
     return(NoValueObject);
 }
 
+Define("%copy-port", CopyPortPrimitive)(long_t argc, FObject argv[])
+{
+    TwoArgsCheck("%copy-port", argc);
+    InputPortArgCheck("%copy-port", argv[0]);
+    if (TextualPortP(argv[0]))
+    {
+        TextualInputPortArgCheck("%copy-port", argv[0]);
+        TextualOutputPortArgCheck("%copy-port", argv[1]);
+
+        for (;;)
+        {
+            FCh ch;
+
+            if (ReadCh(argv[0], &ch) == 0)
+                break;
+            WriteCh(argv[1], ch);
+        }
+    }
+    else
+    {
+        FAssert(BinaryPortP(argv[0]));
+
+        BinaryInputPortArgCheck("%copy-port", argv[0]);
+        BinaryOutputPortArgCheck("%copy-port", argv[1]);
+
+        for (;;)
+        {
+            FByte buf[1024];
+            ulong_t bl = ReadBytes(argv[0], buf, sizeof(buf));
+            if (bl == 0)
+                break;
+            WriteBytes(argv[1], buf, bl);
+        }
+    }
+
+    return(NoValueObject);
+}
+
 Define("socket-merge-flags", SocketMergeFlagsPrimitive)(long_t argc, FObject argv[])
 {
     long_t ret = 0;
@@ -3583,6 +3685,7 @@ static FObject Primitives[] =
     PositioningPortPPrimitive,
     PortPositionPrimitive,
     SetPortPositionPrimitive,
+    CopyPortPrimitive,
     SocketMergeFlagsPrimitive,
     SocketPurgeFlagsPrimitive,
     SocketPPrimitive,
@@ -3599,25 +3702,43 @@ static FObject Primitives[] =
 
 #ifdef FOMENT_UNIX
 static struct termios OriginalTios;
+static int InteractiveConsole = 0;
 
-static void FomentAtExit(void)
-{
-    tcsetattr(0, TCSANOW, &OriginalTios);
-}
-
-static long_t SetupConsole()
+static void SetupTios(void)
 {
     struct termios tios;
 
-    tcgetattr(0, &OriginalTios);
-    atexit(FomentAtExit);
-
     tcgetattr(0, &tios);
     tios.c_iflag = BRKINT;
     tios.c_lflag = ISIG;
     tios.c_cc[VMIN] = 1;
     tios.c_cc[VTIME] = 1;
     tcsetattr(0, TCSANOW, &tios);
+}
+
+static void RestoreTios(void)
+{
+    tcsetattr(0, TCSANOW, &OriginalTios);
+}
+
+void SetupConsoleAgain()
+{
+    if (InteractiveConsole)
+        SetupTios();
+}
+
+void RestoreConsole()
+{
+    if (InteractiveConsole)
+        RestoreTios();
+}
+
+static long_t SetupConsole()
+{
+    tcgetattr(0, &OriginalTios);
+    atexit(RestoreTios);
+
+    SetupTios();
 
     long_t x;
     long_t y;
@@ -3634,7 +3755,7 @@ static void DefineConstant(FObject env, FObject lib, const char * nam, FObject v
     LibraryExport(lib, EnvironmentSetC(env, nam, val));
 }
 
-void ExitFoment()
+void FlushStandardPorts()
 {
     if (TextualPortP(StandardOutput) || BinaryPortP(StandardOutput))
         FlushOutput(StandardOutput);
@@ -3693,8 +3814,9 @@ void SetupIO()
     if (isatty(0) && isatty(1))
     {
         char * term = getenv("TERM");
-        int fi = (term != 0 && strcasecmp(term, "dumb") != 0 && SetupConsole());
-        StandardInput = MakeConsoleInputPort(MakeStringC("console-input"), 0, 1, fi);
+        InteractiveConsole = (term != 0 && strcasecmp(term, "dumb") != 0 && SetupConsole());
+        StandardInput = MakeConsoleInputPort(MakeStringC("console-input"), 0, 1,
+                InteractiveConsole);
         StandardOutput = MakeConsoleOutputPort(MakeStringC("console-output"), 1);
     }
     else
diff --git a/src/io.hpp b/src/io.hpp
index bb5b8a9..7ca08ba 100644
--- a/src/io.hpp
+++ b/src/io.hpp
@@ -27,7 +27,8 @@ typedef struct
 
 FObject MakeBinaryPort(FObject nam, FObject obj, void * ctx, FCloseInputFn cifn,
     FCloseOutputFn cofn, FFlushOutputFn fofn, FReadBytesFn rbfn, FByteReadyPFn brpfn,
-    FWriteBytesFn wbfn, FGetPositionFn gpfn, FSetPositionFn spfn);
+    FWriteBytesFn wbfn, FGetPositionFn gpfn, FSetPositionFn spfn,
+    FGetFileHandleFn gfhfn, ulong_t flgs);
 
 // ---- Textual Ports ----
 
@@ -50,7 +51,8 @@ typedef struct
 
 FObject MakeTextualPort(FObject nam, FObject obj, void * ctx, FCloseInputFn cifn,
     FCloseOutputFn cofn, FFlushOutputFn fofn, FReadChFn rcfn, FCharReadyPFn crpfn,
-    FWriteStringFn wsfn, FGetPositionFn gpfn, FSetPositionFn spfn);
+    FWriteStringFn wsfn, FGetPositionFn gpfn, FSetPositionFn spfn, FGetFileHandleFn gfhfn,
+    ulong_t flgs);
 
 inline FObject CurrentInputPort()
 {
@@ -74,10 +76,18 @@ inline FObject CurrentOutputPort()
     return(port);
 }
 
+FObject OpenInputPipe(FFileHandle fh);
+FObject OpenOutputPipe(FFileHandle fh);
+
 // ----------------
 
 void SetupWrite();
 void SetupRead();
 long_t IdentifierSubsequentP(FCh ch);
 
+#ifdef FOMENT_UNIX
+void SetupConsoleAgain();
+void RestoreConsole();
+#endif // FOMENT_UNIX
+
 #endif // __IO_HPP__
diff --git a/src/main.cpp b/src/main.cpp
index 5a63693..c1a6e24 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -155,7 +155,7 @@ static int RunProgram(FChS * arg)
         ReadLine(port);
 
     ExecuteProc(CompileProgram(nam, port));
-    ExitFoment();
+    FlushStandardPorts();
     return(0);
 }
 
@@ -769,7 +769,7 @@ int main(int argc, FChS * argv[])
         if ((BinaryPortP(StandardOutput) || TextualPortP(StandardOutput))
                 && OutputPortOpenP(StandardOutput))
             WriteSimple(StandardOutput, obj, 0);
-        ExitFoment();
+        FlushStandardPorts();
         return(1);
     }
 
@@ -779,7 +779,7 @@ int main(int argc, FChS * argv[])
     {
         if (ProcessOptions(LateConfig, argc, argv, &pdx) == 0)
         {
-            ExitFoment();
+            FlushStandardPorts();
             return(1);
         }
 
@@ -811,12 +811,12 @@ int main(int argc, FChS * argv[])
                 return(1);
             }
             ExecuteProc(CompileProgram(AsGenericPort(StandardInput)->Name, StandardInput));
-            ExitFoment();
+            FlushStandardPorts();
             break;
 
         case InteractiveMode:
             ExecuteProc(InteractiveThunk);
-            ExitFoment();
+            FlushStandardPorts();
             break;
 
         default:
@@ -831,7 +831,7 @@ int main(int argc, FChS * argv[])
             WriteStringC(StandardOutput, "exception: ");
         WriteSimple(StandardOutput, obj, 0);
         WriteCh(StandardOutput, '\n');
-        ExitFoment();
+        FlushStandardPorts();
         return(1);
     }
 }
diff --git a/src/process.cpp b/src/process.cpp
new file mode 100644
index 0000000..f67ff57
--- /dev/null
+++ b/src/process.cpp
@@ -0,0 +1,558 @@
+/*
+
+Foment
+
+- %subprocess: textual vs binary port when a pipe is created
+*/
+
+#ifdef FOMENT_WINDOWS
+#include <windows.h>
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+#include <string.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#endif // FOMENT_UNIX
+
+#include <stdio.h>
+#include "foment.hpp"
+#include "syncthrd.hpp"
+#include "io.hpp"
+#include "unicode.hpp"
+
+#if defined(FOMENT_BSD) || defined(FOMENT_OSX)
+extern char ** environ;
+#else
+#include <malloc.h>
+#endif
+
+// ----------------
+
+EternalSymbol(StdoutSymbol, "stdout");
+
+// ---- Subprocesses ----
+
+typedef struct
+{
+#ifdef FOMENT_WINDOWS
+    DWORD ProcessID;
+    HANDLE ProcessHandle;
+    DWORD Status;
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+    pid_t ProcessID;
+    int Status;
+    int Done;
+#endif // FOMENT_UNIX
+} FSubprocess;
+
+#define AsSubprocess(obj) ((FSubprocess *) (obj))
+#define SubprocessP(obj) (IndirectTag(obj) == SubprocessTag)
+
+#ifdef FOMENT_WINDOWS
+static FObject MakeSubprocess(DWORD pid, HANDLE ph, const char * who)
+{
+    FSubprocess * sub = (FSubprocess *) MakeObject(SubprocessTag, sizeof(FSubprocess), 0, who);
+    sub->ProcessID = pid;
+    sub->ProcessHandle = ph;
+    return(sub);
+}
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+static FObject MakeSubprocess(pid_t pid, const char * who)
+{
+    FSubprocess * sub = (FSubprocess *) MakeObject(SubprocessTag, sizeof(FSubprocess), 0, who);
+    sub->ProcessID = pid;
+    sub->Status = 0;
+    sub->Done = 0;
+    return(sub);
+}
+#endif // FOMENT_UNIX
+
+void WriteSubprocess(FWriteContext * wctx, FObject obj)
+{
+    FCh s[16];
+    long_t sl = FixnumAsString((long_t) obj, s, 16);
+
+    wctx->WriteStringC("#<subprocess: ");
+    wctx->WriteString(s, sl);
+    wctx->WriteStringC(" pid: ");
+
+    FAssert(SubprocessP(obj));
+
+    sl = FixnumAsString((long_t) AsSubprocess(obj)->ProcessID, s, 10);
+    wctx->WriteString(s, sl);
+    wctx->WriteCh('>');
+}
+
+inline void SubprocessArgCheck(const char * who, FObject obj)
+{
+    if (SubprocessP(obj) == 0)
+        RaiseExceptionC(Assertion, who, "expected a subprocess", List(obj));
+}
+
+static void MakePipe(FFileHandle * ifh, FFileHandle * ofh, const char * who)
+{
+#ifdef FOMENT_WINDOWS
+    if (CreatePipe(ifh, ofh, 0, 0) == 0)
+        RaiseExceptionC(Assertion, who, "create pipe failed", List(MakeFixnum(GetLastError())));
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+    int pipefd[2];
+
+    if (pipe(pipefd) != 0)
+        RaiseExceptionC(Assertion, who, "pipe system call failed", List(MakeFixnum(errno)));
+    *ifh = pipefd[0];
+    *ofh = pipefd[1];
+#endif // FOMENT_UNIX
+}
+
+static FChS * ConvertStringToSystem(FObject s)
+{
+    FAssert(StringP(s));
+
+#ifdef FOMENT_WINDOWS
+        FObject bv = ConvertStringToUtf16(s);
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+        FObject bv = ConvertStringToUtf8(s);
+#endif // FOMENT_UNIX
+
+        FAssert(BytevectorP(bv));
+
+        return((FChS *) AsBytevector(bv)->Vector);
+}
+
+typedef struct
+{
+    // Optional file handles to use for stdout, stdin, and stderr in the subprocess.
+    FFileHandle ChildStdout; // Output file handle.
+    FFileHandle ChildStdin; // Input file handle.
+    FFileHandle ChildStderr; // Output file handle.
+    int UseStdout; // Use stdout for stderr.
+
+    // These are only used if the corresponding Child* above is not specified.
+    FFileHandle PipeStdout; // Input file handle of a pipe connected to stdout in the subprocess.
+    FFileHandle PipeStdin; // Output file handle of a pipe connected to stdin in the subprocess.
+    FFileHandle PipeStderr; // Input file handle of a pipe connected to stderr in the subprocess.
+} FSubprocessFileHandles;
+
+#ifdef FOMENT_WINDOWS
+static FChS * CopyArg(FChS * cmd, FChS * arg)
+{
+    *cmd = '"';
+    cmd += 1;
+
+    while (*arg != 0)
+    {
+        if (*arg == '"') // || *arg == '\\')
+        {
+            *cmd = '\\';
+            cmd += 1;
+        }
+        *cmd = *arg;
+        cmd += 1;
+        arg += 1;
+    }
+
+    *cmd = '"';
+    cmd += 1;
+    return(cmd);
+}
+
+static void ChildArgs(long_t argc, FObject argv[], FChS ** app, FChS ** cmdline)
+{
+    long_t cmdlen = 1;
+    long_t adx;
+
+    for (adx = 0; adx < argc; adx++)
+        cmdlen += StringLength(argv[adx]) * 2 + 3;
+
+    FObject bv = MakeBytevector(cmdlen * sizeof(FChS));
+    FAssert(BytevectorP(bv));
+    FChS * cmd = (FChS *) AsBytevector(bv)->Vector;
+    *cmdline = cmd;
+
+    for (adx = 0; adx < argc; adx++)
+    {
+        FChS * arg = ConvertStringToSystem(argv[adx]);
+        if (adx == 0)
+        {
+            *app = arg;
+            FChS * s = wcsrchr(arg, '\\');
+            if (s != 0)
+                arg = s + 1;
+            cmd = CopyArg(cmd, arg);
+        }
+        else
+        {
+            *cmd = ' ';
+            cmd += 1;
+            cmd = CopyArg(cmd, arg);
+        }
+    }
+    *cmd = 0;
+}
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+static void ChildFailed(char * cmd, const char * call)
+{
+    fprintf(stderr, "error: %s: %s: %d\n", cmd, call, errno);
+    fflush(stderr);
+    exit(1);
+}
+
+static void ChildProcess(FSubprocessFileHandles * sfh, FFileHandle chldin, FFileHandle chldout,
+    FFileHandle chlderr, long_t argc, FObject argv[])
+{
+    FAssert(argc > 0);
+
+    char ** args = (char **) malloc(sizeof(char *) * (argc + 1));
+    char * cmd = ConvertStringToSystem(argv[0]);
+    char * s = strrchr(cmd, '/');
+    if (s == 0)
+        args[0] = cmd;
+    else
+        args[0] = strdup(s + 1);
+
+    for (long_t adx = 1; adx < argc; adx += 1)
+        args[adx] = ConvertStringToSystem(argv[adx]);
+    args[argc] = 0;
+
+    if (sfh->PipeStdout != INVALID_FILE_HANDLE)
+        close(sfh->PipeStdout);
+    if (sfh->PipeStdin != INVALID_FILE_HANDLE)
+        close(sfh->PipeStdin);
+    if (sfh->UseStdout == 0 && sfh->PipeStderr != INVALID_FILE_HANDLE)
+        close(sfh->PipeStderr);
+
+    while (chldin < 3)
+        chldin = dup(chldin);
+    while (chldout < 3)
+        chldout = dup(chldout);
+    while (chlderr < 3)
+        chlderr = dup(chlderr);
+
+    close(0);
+    if (dup2(chldin, 0) != 0)
+        ChildFailed(cmd, "dup2");
+    close(1);
+    if (dup2(chldout, 1) != 1)
+        ChildFailed(cmd, "dup2");
+    close(2);
+    if (dup2(chlderr, 2) != 2)
+        ChildFailed(cmd, "dup2");
+    close(chldin);
+    close(chldout);
+    close(chlderr);
+
+    execve(cmd, args, environ);
+    ChildFailed(cmd, "execve");
+}
+#endif // FOMENT_UNIX
+
+static FObject Subprocess(FSubprocessFileHandles * sfh, long_t argc, FObject argv[],
+    const char * who)
+{
+    FFileHandle chldout, chldin, chlderr;
+
+    if (sfh->ChildStdout == INVALID_FILE_HANDLE)
+    {
+        MakePipe(&(sfh->PipeStdout), &chldout, who);
+#ifdef FOMENT_WINDOWS
+        SetHandleInformation(chldout, HANDLE_FLAG_INHERIT, HANDLE_FLAG_INHERIT);
+#endif // FOMENT_WINDOWS
+    }
+    else
+        chldout = sfh->ChildStdout;
+
+    if (sfh->ChildStdin == INVALID_FILE_HANDLE)
+    {
+        MakePipe(&chldin, &(sfh->PipeStdin), who);
+#ifdef FOMENT_WINDOWS
+        SetHandleInformation(chldin, HANDLE_FLAG_INHERIT, HANDLE_FLAG_INHERIT);
+#endif // FOMENT_WINDOWS
+    }
+    else
+        chldin = sfh->ChildStdin;
+
+    if (sfh->UseStdout)
+        chlderr = chldout;
+    else if (sfh->ChildStderr == INVALID_FILE_HANDLE)
+    {
+        MakePipe(&(sfh->PipeStderr), &chlderr, who);
+#ifdef FOMENT_WINDOWS
+        SetHandleInformation(chlderr, HANDLE_FLAG_INHERIT, HANDLE_FLAG_INHERIT);
+#endif // FOMENT_WINDOWS
+    }
+    else
+        chlderr = sfh->ChildStderr;
+
+    FlushStandardPorts();
+
+#ifdef FOMENT_WINDOWS
+    FChS *app;
+    FChS *cmdline;
+    ChildArgs(argc, argv, &app, &cmdline);
+
+    STARTUPINFOW si;
+    memset(&si, 0, sizeof(si));
+    si.cb = sizeof(si);
+    si.dwFlags = STARTF_USESTDHANDLES;
+    si.hStdInput = chldin;
+    si.hStdOutput = chldout;
+    si.hStdError = chlderr;
+
+    PROCESS_INFORMATION pi;
+    BOOL ret = CreateProcessW(app, cmdline, NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi);
+    if (ret == 0)
+        RaiseExceptionC(Assertion, who, "create process system call failed",
+                List(MakeIntegerFromUInt64(GetLastError())));
+
+    CloseHandle(pi.hThread);
+
+    if (sfh->PipeStdout != INVALID_FILE_HANDLE)
+        CloseHandle(chldout);
+
+    if (sfh->PipeStdin != INVALID_FILE_HANDLE)
+        CloseHandle(chldin);
+
+    if (sfh->UseStdout == 0 && sfh->PipeStderr != INVALID_FILE_HANDLE)
+        CloseHandle(chlderr);
+
+    return(MakeSubprocess(pi.dwProcessId, pi.hProcess, who));
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+    RestoreConsole();
+
+    pid_t pid = fork();
+    if (pid < 0)
+        RaiseExceptionC(Assertion, who, "fork system call failed", List(MakeFixnum(errno)));
+
+    if (pid == 0)
+    {
+        ChildProcess(sfh, chldin, chldout, chlderr, argc, argv);
+
+        // Never returns.
+        FAssert(0);
+    }
+
+    // Parent.
+
+    SetupConsoleAgain();
+
+    if (sfh->PipeStdout != INVALID_FILE_HANDLE)
+        close(chldout);
+
+    if (sfh->PipeStdin != INVALID_FILE_HANDLE)
+        close(chldin);
+
+    if (sfh->UseStdout == 0 && sfh->PipeStderr != INVALID_FILE_HANDLE)
+        close(chlderr);
+
+    return(MakeSubprocess(pid, who));
+#endif // FOMENT_UNIX
+}
+
+Define("%subprocess", SubprocessPrimitive)(long_t argc, FObject argv[])
+{
+    AtLeastFiveArgsCheck("%subprocess", argc);
+    BooleanArgCheck("%subprocess", argv[0]);
+
+    for (long_t adx = 4; adx < argc; adx += 1)
+        StringArgCheck("%subprocess", argv[adx]);
+
+    FSubprocessFileHandles sfh;
+
+    if (argv[1] == FalseObject)
+        sfh.ChildStdout = INVALID_FILE_HANDLE;
+    else
+    {
+        OutputPortArgCheck("%subprocess", argv[1]);
+
+        sfh.ChildStdout = GetFileHandle(argv[1]);
+        if (argv[0] == FalseObject && sfh.ChildStdout == INVALID_FILE_HANDLE)
+            RaiseExceptionC(Assertion, "%subprocess", "expected an output file handle port",
+                    List(argv[1]));
+    }
+
+    if (argv[2] == FalseObject)
+        sfh.ChildStdin = INVALID_FILE_HANDLE;
+    else
+    {
+        InputPortArgCheck("%subprocess", argv[2]);
+
+        sfh.ChildStdin = GetFileHandle(argv[2]);
+        if (argv[0] == FalseObject && sfh.ChildStdin == INVALID_FILE_HANDLE)
+            RaiseExceptionC(Assertion, "%subprocess", "expected an input file handle port",
+                    List(argv[2]));
+    }
+
+    sfh.ChildStderr = INVALID_FILE_HANDLE;
+    sfh.UseStdout = 0;
+
+    if (argv[3] == StdoutSymbol)
+        sfh.UseStdout = 1;
+    else if (argv[3] != FalseObject)
+    {
+        OutputPortArgCheck("%subprocess", argv[3]);
+
+        sfh.ChildStderr = GetFileHandle(argv[3]);
+        if (argv[0] == FalseObject && sfh.ChildStderr == INVALID_FILE_HANDLE)
+            RaiseExceptionC(Assertion, "%subprocess", "expected an output file handle port",
+                    List(argv[3]));
+    }
+
+    sfh.PipeStdout = INVALID_FILE_HANDLE;
+    sfh.PipeStdin = INVALID_FILE_HANDLE;
+    sfh.PipeStderr = INVALID_FILE_HANDLE;
+
+    FObject sub = Subprocess(&sfh, argc - 4, argv + 4, "%subprocess");
+
+    FAssert(SubprocessP(sub));
+
+    FObject out = (sfh.ChildStdout == INVALID_FILE_HANDLE) ? OpenInputPipe(sfh.PipeStdout) :
+        FalseObject;
+
+    FObject in = (sfh.ChildStdin == INVALID_FILE_HANDLE) ? OpenOutputPipe(sfh.PipeStdin) :
+        FalseObject;
+
+    FObject err = (sfh.UseStdout == 0 && sfh.ChildStderr == INVALID_FILE_HANDLE) ?
+        OpenInputPipe(sfh.PipeStderr) : FalseObject;
+
+    return(List(sub, out, in, err));
+}
+
+Define("subprocess?", SubprocessPPrimitive)(long_t argc, FObject argv[])
+{
+    OneArgCheck("subprocess?", argc);
+
+    return(SubprocessP(argv[0]) ? TrueObject : FalseObject);
+}
+
+Define("subprocess-wait", SubprocessWaitPrimitive)(long_t argc, FObject argv[])
+{
+    OneArgCheck("subprocess-wait", argc);
+    SubprocessArgCheck("subprocess-wait", argv[0]);
+
+    FSubprocess * sub = AsSubprocess(argv[0]);
+
+#ifdef FOMENT_WINDOWS
+    if (sub->ProcessHandle != INVALID_HANDLE_VALUE)
+    {
+        if (WaitForSingleObject(sub->ProcessHandle, INFINITE) == WAIT_FAILED)
+            RaiseExceptionC(Assertion, "subprocess-wait",
+                    "wait for single object system call failed",
+                    List(MakeIntegerFromUInt64(GetLastError())));
+
+        DWORD status;
+        GetExitCodeProcess(sub->ProcessHandle, &status);
+        sub->Status = status;
+
+        CloseHandle(sub->ProcessHandle);
+        sub->ProcessHandle = INVALID_HANDLE_VALUE;
+    }
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+    if (sub->Done == 0)
+    {
+        int status;
+        if (waitpid(sub->ProcessID, &status, 0) < 0)
+            RaiseExceptionC(Assertion, "subprocess-wait", "waitpid failed",
+                    List(MakeFixnum(errno)));
+
+        sub->Done = 1;
+        sub->Status = status;
+    }
+#endif // FOMENT_UNIX
+
+    return(NoValueObject);
+}
+
+Define("subprocess-status", SubprocessStatusPrimitive)(long_t argc, FObject argv[])
+{
+    OneArgCheck("subprocess-status", argc);
+    SubprocessArgCheck("subprocess-status", argv[0]);
+
+    FSubprocess * sub = AsSubprocess(argv[0]);
+
+#ifdef FOMENT_WINDOWS
+    if (sub->ProcessHandle != INVALID_HANDLE_VALUE)
+        return(StringCToSymbol("running"));
+
+    return(MakeIntegerFromUInt64(sub->Status));
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+    if (sub->Done == 0)
+        return(StringCToSymbol("running"));
+
+    if (WIFEXITED(sub->Status))
+        return(MakeFixnum(WEXITSTATUS(sub->Status)));
+
+    FAssert(WIFSIGNALED(sub->Status));
+
+    return(MakeFixnum(WTERMSIG(sub->Status)));
+#endif // FOMENT_UNIX
+}
+
+Define("subprocess-kill", SubprocessKillPrimitive)(long_t argc, FObject argv[])
+{
+    TwoArgsCheck("subprocess-kill", argc);
+    SubprocessArgCheck("subprocess-kill", argv[0]);
+
+    FSubprocess * sub = AsSubprocess(argv[0]);
+
+#ifdef FOMENT_WINDOWS
+    if (sub->ProcessHandle != INVALID_HANDLE_VALUE && argv[1] != FalseObject)
+        TerminateProcess(sub->ProcessHandle, 0);
+#endif // FOMENT_WINDOWS
+
+#ifdef FOMENT_UNIX
+    if (sub->Done == 0)
+        kill(sub->ProcessID, argv[1] == FalseObject ? SIGINT : SIGTERM);
+#endif // FOMENT_UNIX
+
+    return(NoValueObject);
+}
+
+Define("subprocess-pid", SubprocessPIDPrimitive)(long_t argc, FObject argv[])
+{
+    OneArgCheck("subprocess-pid", argc);
+    SubprocessArgCheck("subprocess-pid", argv[0]);
+
+    return(MakeFixnum(AsSubprocess(argv[0])->ProcessID));
+}
+
+static FObject Primitives[] =
+{
+    SubprocessPrimitive,
+    SubprocessPPrimitive,
+    SubprocessWaitPrimitive,
+    SubprocessStatusPrimitive,
+    SubprocessKillPrimitive,
+    SubprocessPIDPrimitive
+};
+
+void SetupProcess()
+{
+    StdoutSymbol = InternSymbol(StdoutSymbol);
+
+    FAssert(StdoutSymbol == StringCToSymbol("stdout"));
+
+    for (ulong_t idx = 0; idx < sizeof(Primitives) / sizeof(FPrimitive *); idx++)
+        DefinePrimitive(Bedrock, BedrockLibrary, Primitives[idx]);
+}
diff --git a/src/syncthrd.cpp b/src/syncthrd.cpp
index 384e021..108e68e 100644
--- a/src/syncthrd.cpp
+++ b/src/syncthrd.cpp
@@ -253,7 +253,7 @@ void ThreadExit(FObject obj)
 
     if (LeaveThread(ts) == 0)
     {
-        ExitFoment();
+        FlushStandardPorts();
 
         exit(0);
     }
@@ -281,7 +281,7 @@ Define("%exit", ExitPrimitive)(long_t argc, FObject argv[])
 {
     ZeroOrOneArgsCheck("exit", argc);
 
-    ExitFoment();
+    FlushStandardPorts();
     if (argc == 0 || argv[0] == TrueObject)
         exit(0);
     if (FixnumP(argv[0]))
diff --git a/test/exitcode.cpp b/test/exitcode.cpp
new file mode 100644
index 0000000..a178ee4
--- /dev/null
+++ b/test/exitcode.cpp
@@ -0,0 +1,14 @@
+/*
+
+Exit with the code specified as an argument.
+
+*/
+
+#include <stdlib.h>
+
+int main(int argc, char * argv[])
+{
+    if (argc != 2)
+        return(1);
+    return(atoi(argv[1]));
+}
diff --git a/test/hang.cpp b/test/hang.cpp
new file mode 100644
index 0000000..a09ecde
--- /dev/null
+++ b/test/hang.cpp
@@ -0,0 +1,15 @@
+/*
+
+Hang.
+
+*/
+
+int main(int argc, char * argv[])
+{
+    int cnt = 0;
+
+    for (;;)
+        cnt += 1;
+
+    return(0);
+}
diff --git a/test/process.scm b/test/process.scm
new file mode 100644
index 0000000..62a9383
--- /dev/null
+++ b/test/process.scm
@@ -0,0 +1,311 @@
+;;;
+;;; Processes
+;;;
+
+(import (foment base))
+
+(check-equal #t #t)
+
+(define (read-lines port)
+    (let ((s (read-line port)))
+        (if (eof-object? s)
+            '()
+            (cons s (read-lines port)))))
+
+(define stdread
+    (cond-expand
+        (windows "..\\windows\\debug\\stdread.exe")
+        (else "../unix/debug/stdread")))
+
+(define stdwrite
+    (cond-expand
+        (windows "..\\windows\\debug\\stdwrite.exe")
+        (else "../unix/debug/stdwrite")))
+
+(define exitcode
+    (cond-expand
+        (windows "..\\windows\\debug\\exitcode.exe")
+        (else "../unix/debug/exitcode")))
+
+(define hang
+    (cond-expand
+        (windows "..\\windows\\debug\\hang.exe")
+        (else "../unix/debug/hang")))
+
+;; subprocess
+
+(check-equal 0
+    (call-with-values
+        (lambda ()
+            (subprocess (current-output-port) #f (current-error-port)
+                    stdread "ABC" "DEF GHI" "JKLMNOPQR"))
+        (lambda (sub in out err)
+            (for-each
+                (lambda (line)
+                    (display line out)
+                    (newline out))
+                '("ABC" "DEF GHI" "JKLMNOPQR"))
+            (close-port out)
+            (subprocess-wait sub)
+            (subprocess-status sub))))
+
+(check-equal ("abc" "def\\ghi" "jklmn\"opqr")
+    (call-with-values
+        (lambda ()
+            (subprocess #f (current-input-port) (current-error-port)
+                    stdwrite "--stdout" "abc" "def\\ghi" "jklmn\"opqr"))
+        (lambda (sub in out err)
+            (let ((lines (read-lines in)))
+                (close-port in)
+                (subprocess-wait sub)
+                (if (zero? (subprocess-status sub))
+                    lines
+                    #f)))))
+
+(check-equal ("abc" "defghi" "jklmnopqr")
+    (call-with-values
+        (lambda ()
+            (subprocess #f (current-input-port) 'stdout
+                    stdwrite "--stderr" "abc" "defghi" "jklmnopqr"))
+        (lambda (sub in out err)
+            (let ((lines (read-lines in)))
+                (close-port in)
+                (subprocess-wait sub)
+                (if (zero? (subprocess-status sub))
+                    lines
+                    #f)))))
+
+(check-equal ("abc" "defghi" "jklmnopqr")
+    (call-with-values
+        (lambda ()
+            (subprocess (current-output-port) (current-input-port) #f
+                    stdwrite "--stderr" "abc" "defghi" "jklmnopqr"))
+        (lambda (sub in out err)
+            (let ((lines (read-lines err)))
+                (close-port err)
+                (subprocess-wait sub)
+                (if (zero? (subprocess-status sub))
+                    lines
+                    #f)))))
+
+(check-equal 234
+    (call-with-values
+        (lambda ()
+            (subprocess (current-output-port) (current-input-port) (current-error-port)
+                    exitcode "234"))
+        (lambda (sub in out err)
+            (subprocess-wait sub)
+            (subprocess-status sub))))
+
+;; subprocess-wait
+;; subprocess-status
+;; subprocess-kill
+;; subprocess-pid
+;; subprocess?
+
+(define-values (sub1 in1 out1 err1) (subprocess #f #f 'stdout hang))
+(check-equal #t (subprocess? sub1))
+(check-equal #f (subprocess? in1))
+(check-equal #f err1)
+(check-equal #t (input-port-open? in1))
+(check-equal #t (output-port-open? out1))
+
+(check-equal running (subprocess-status sub1))
+(check-equal #t (and (integer? (subprocess-pid sub1)) (> (subprocess-pid sub1) 0)))
+
+(subprocess-kill sub1 #t)
+(subprocess-wait sub1)
+(check-equal #t (integer? (subprocess-status sub1)))
+
+(close-port in1)
+(close-port out1)
+
+;; process/ports
+;; process*/ports
+
+(check-equal 0
+    (let* ((lst (process*/ports (current-output-port) #f (current-error-port)
+                    stdread "ABC" "DEFGHI" "JKLMNOPQR"))
+            (out (cadr lst))
+            (ctrl (cadddr (cdr lst))))
+        (for-each
+            (lambda (line)
+                (display line out)
+                (newline out))
+            '("ABC" "DEFGHI" "JKLMNOPQR"))
+        (close-port out)
+        (ctrl 'wait)
+        (ctrl 'exit-code)))
+
+(check-equal ("abc" "defghi" "jklmnopqr")
+    (let* ((lst (process*/ports #f (current-input-port) (current-error-port)
+                        stdwrite "--stdout" "abc" "defghi" "jklmnopqr"))
+            (in (car lst))
+            (ctrl (cadddr (cdr lst))))
+        (let ((lines (read-lines in)))
+            (close-port in)
+            (ctrl 'wait)
+            (if (zero? (ctrl 'exit-code))
+                lines
+                #f))))
+
+(check-equal ("abc" "defghi" "jklmnopqr")
+    (let* ((lst (process/ports #f (current-input-port) 'stdout
+                        "stdwrite --stderr abc defghi jklmnopqr"))
+            (in (car lst))
+            (ctrl (cadddr (cdr lst))))
+        (let ((lines (read-lines in)))
+            (close-port in)
+            (ctrl 'wait)
+            (if (zero? (ctrl 'exit-code))
+                lines
+                #f))))
+
+(check-equal ("abc" "defghi" "jklmnopqr")
+    (let* ((lst (process*/ports (current-output-port) (current-input-port) #f
+                        stdwrite "--stderr" "abc" "defghi" "jklmnopqr"))
+            (err (cadddr lst))
+            (ctrl (cadddr (cdr lst))))
+        (let ((lines (read-lines err)))
+            (close-port err)
+            (ctrl 'wait)
+            (if (zero? (ctrl 'exit-code))
+                lines
+                #f))))
+
+(check-equal 123
+    (let* ((lst (process*/ports (current-output-port) (current-input-port) (current-error-port)
+                        exitcode "123"))
+            (ctrl (cadddr (cdr lst))))
+            (ctrl 'wait)
+            (ctrl 'exit-code)))
+
+;; (<ctrl> 'status)
+;; (<ctrl> 'exit-code)
+;; (<ctrl> 'wait)
+;; (<ctrl> 'kill)
+
+(define p2 (process*/ports #f #f 'stdout hang))
+(define in2 (car p2))
+(define out2 (cadr p2))
+(check-equal #t
+    (let ((pid (caddr p2)))
+        (and (integer? pid) (> pid 0))))
+(define err2 (cadddr p2))
+(define ctrl2 (cadddr (cdr p2)))
+
+(check-equal #f err2)
+(check-equal #t (input-port-open? in2))
+(check-equal #t (output-port-open? out2))
+
+(check-equal running (ctrl2 'status))
+(check-equal #f (ctrl2 'exit-code))
+
+(ctrl2 'kill)
+(ctrl2 'wait)
+(check-equal #t
+    (eq? (cond-expand (windows 'done-ok) (else 'done-error))
+        (ctrl2 'status)))
+
+(check-equal #t (integer? (ctrl2 'exit-code)))
+
+;; system
+;; system*
+
+(define (with-output-to-string proc)
+    (let ((port (open-output-string)))
+        (parameterize ((current-output-port port)) (proc))
+        (get-output-string port)))
+
+(check-equal #t
+    (string=? (substring "abcdefghijklmnopqr" 0 18)
+        (substring
+            (with-output-to-string
+                (lambda ()
+                    (system "stdwrite --stdout abcdefghijklmnopqr")))
+            0 18)))
+
+(define (with-input-from-string s proc)
+    (let ((port (open-input-string s)))
+        (parameterize ((current-input-port port)) (proc))))
+
+(check-equal #t
+    (with-input-from-string "abcdef\n"
+        (lambda ()
+            (system* stdread "abcdef"))))
+
+(check-equal #f
+    (with-input-from-string "abcdef"
+        (lambda ()
+            (system* stdread "abc" "def"))))
+
+;; system/exit-code
+;; system*/exit-code
+
+(check-equal 88
+    (system/exit-code "exitcode 88"))
+
+(check-equal 88
+    (system*/exit-code exitcode "88"))
+
+;; chicken process module
+
+(define (call-with-input-pipe cmdline proc)
+    (let* ((lst (process/ports #f (current-input-port) (current-error-port) cmdline))
+            (in (car lst))
+            (ctrl (cadddr (cdr lst))))
+        (let-values ((results (proc in)))
+            (close-port in)
+            (ctrl 'wait)
+            (if (= (ctrl 'exit-code) 0)
+                (apply values results)
+                #f))))
+
+(check-equal ("aaa" "bbb" "ccc" "ddd")
+    (call-with-input-pipe "stdwrite --stdout aaa bbb ccc ddd"
+        (lambda (in) (read-lines in))))
+
+(define (call-with-output-pipe cmdline proc)
+    (let* ((lst (process/ports (current-output-port) #f (current-error-port) cmdline))
+            (out (cadr lst))
+            (ctrl (cadddr (cdr lst))))
+        (let-values ((results (proc out)))
+            (close-port out)
+            (ctrl 'wait)
+            (if (= (ctrl 'exit-code) 0)
+                (apply values results)
+                #f))))
+
+(check-equal #t
+    (call-with-output-pipe "stdread 1 22 333 4444 55555"
+        (lambda (out)
+            (for-each
+                (lambda (line)
+                    (display line out)
+                    (newline out))
+                '("1" "22" "333" "4444" "55555"))
+            #t)))
+
+(define (with-input-from-pipe cmdline proc)
+    (call-with-input-pipe cmdline
+        (lambda (port)
+            (parameterize ((current-input-port port)) (proc)))))
+
+(check-equal ("aaa" "bbb" "ccc" "ddd")
+    (with-input-from-pipe "stdwrite --stdout aaa bbb ccc ddd"
+        (lambda () (read-lines (current-input-port)))))
+
+(define (with-output-to-pipe cmdline proc)
+    (call-with-output-pipe cmdline
+        (lambda (port)
+            (parameterize ((current-output-port port)) (proc)))))
+
+(check-equal #t
+    (with-output-to-pipe "stdread 1 22 333 4444 55555"
+        (lambda ()
+            (for-each
+                (lambda (line)
+                    (display line)
+                    (newline))
+                '("1" "22" "333" "4444" "55555"))
+            #t)))
diff --git a/test/stdread.cpp b/test/stdread.cpp
new file mode 100644
index 0000000..fccadae
--- /dev/null
+++ b/test/stdread.cpp
@@ -0,0 +1,30 @@
+/*
+
+Read lines from standard input; each line should match one argument.
+
+*/
+
+#include <string.h>
+#include <stdio.h>
+
+int main(int argc, char * argv[])
+{
+    char s[1024];
+    int adx = 1;
+
+    for (;;)
+    {
+        if (fgets(s, sizeof(s), stdin) == 0)
+            break;
+        if (adx == argc)
+            return(1);
+        size_t sl = strlen(s);
+        if (sl > 0)
+            s[sl - 1] = 0;
+        if (strcmp(s, argv[adx]) != 0)
+            return(2);
+        adx += 1;
+    }
+
+    return(0);
+}
diff --git a/test/stdwrite.cpp b/test/stdwrite.cpp
new file mode 100644
index 0000000..dbcb818
--- /dev/null
+++ b/test/stdwrite.cpp
@@ -0,0 +1,30 @@
+/*
+
+Write lines to standard output or error; each line is an argument.
+
+*/
+
+#include <string.h>
+#include <stdio.h>
+
+int main(int argc, char * argv[])
+{
+    FILE * fp;
+
+    if (argc < 2)
+        return(1);
+    if (strcmp(argv[1], "--stdout") == 0)
+        fp = stdout;
+    else if (strcmp(argv[1], "--stderr") == 0)
+        fp = stderr;
+    else
+        return(2);
+
+    for (int adx = 2; adx < argc; adx += 1)
+    {
+        fputs(argv[adx], fp);
+        fputc('\n', fp);
+    }
+
+    return(0);
+}
diff --git a/unix/makefile b/unix/makefile
index a048ed9..a45488a 100644
--- a/unix/makefile
+++ b/unix/makefile
@@ -2,7 +2,6 @@
 # Foment
 #
 
-CC ?= gcc
 CXX ?= g++
 BUILD_CXX ?= g++
 
@@ -39,7 +38,7 @@ clean: debug release profile
 	-rm profile/*
 
 .PHONY: test
-test: all foment-test stress-test chibi-test
+test: all foment-test stress-test chibi-test process-test
 
 .PHONY: test-all
 test-all: all
@@ -72,6 +71,10 @@ stress-test: all
 chibi-test: all
 	cd ../test ; ../unix/$(TEST_BUILD)/foment $(TEST_OPTIONS) r7rs-tests.scm
 
+.PHONY: process-test
+process-test: all debug/stdread debug/stdwrite debug/exitcode debug/hang
+	PATH=../unix/debug:$(PATH) ; cd ../test ; ../unix/$(TEST_BUILD)/foment $(TEST_OPTIONS) runtests.scm process.scm
+
 debug:
 	-mkdir debug
 
@@ -93,7 +96,7 @@ debug/foment: debug/foment.o debug/gc.o debug/syncthrd.o debug/compile.o debug/i
 		debug/pairs.o debug/unicode.o debug/chars.o debug/strings.o debug/vectors.o\
 		debug/library.o debug/execute.o debug/numbers.o debug/write.o\
 		debug/read.o debug/filesys.o debug/compare.o debug/main.o debug/hashtbl.o\
-		debug/bignums.o debug/charset.o debug/base.o
+		debug/bignums.o debug/charset.o debug/process.o debug/base.o
 	$(CXX)  $(LDFLAGS) -o debug/foment $^ -lpthread
 
 release/foment: release/foment.o release/gc.o release/syncthrd.o release/compile.o release/io.o\
@@ -102,7 +105,7 @@ release/foment: release/foment.o release/gc.o release/syncthrd.o release/compile
 		release/vectors.o release/library.o release/execute.o release/numbers.o\
 		release/write.o release/read.o release/filesys.o\
 		release/compare.o release/main.o release/hashtbl.o release/bignums.o release/charset.o\
-		release/base.o
+		release/process.o release/base.o
 	$(CXX) $(LDFLAGS) -o release/foment $^ -lpthread
 
 profile/foment: profile/foment.o profile/gc.o profile/syncthrd.o profile/compile.o profile/io.o\
@@ -111,7 +114,7 @@ profile/foment: profile/foment.o profile/gc.o profile/syncthrd.o profile/compile
 		profile/vectors.o profile/library.o profile/execute.o profile/numbers.o\
 		profile/write.o profile/read.o profile/filesys.o\
 		profile/compare.o profile/main.o profile/hashtbl.o profile/bignums.o profile/charset.o\
-		profile/base.o
+		profile/process.o profile/base.o
 	$(CXX)  $(LDFLAGS) -pg -o profile/foment $^ -lpthread
 
 debug/foment.o: ../src/foment.cpp ../src/foment.hpp ../src/syncthrd.hpp ../src/unicode.hpp
@@ -132,6 +135,8 @@ debug/execute.o: ../src/execute.cpp ../src/foment.hpp ../src/execute.hpp ../src/
 debug/numbers.o: ../src/numbers.cpp ../src/foment.hpp ../src/unicode.hpp ../src/bignums.hpp
 debug/bignums.o: ../src/bignums.cpp ../src/foment.hpp ../src/unicode.hpp ../src/bignums.hpp
 debug/charset.o: ../src/charset.cpp ../src/foment.hpp ../src/unicode.hpp ../src/unicrng.hpp
+debug/process.o: ../src/process.cpp ../src/foment.hpp ../src/syncthrd.hpp ../src/io.hpp\
+	../src/unicode.hpp
 debug/io.o: ../src/io.cpp ../src/foment.hpp ../src/syncthrd.hpp ../src/io.hpp\
 	../src/unicode.hpp
 debug/write.o: ../src/write.cpp ../src/foment.hpp ../src/syncthrd.hpp ../src/io.hpp\
@@ -162,6 +167,8 @@ release/execute.o: ../src/execute.cpp ../src/foment.hpp ../src/execute.hpp ../sr
 release/numbers.o: ../src/numbers.cpp ../src/foment.hpp ../src/unicode.hpp ../src/bignums.hpp
 release/bignums.o: ../src/bignums.cpp ../src/foment.hpp ../src/unicode.hpp ../src/bignums.hpp
 release/charset.o: ../src/charset.cpp ../src/foment.hpp ../src/unicode.hpp ../src/unicrng.hpp
+release/process.o: ../src/process.cpp ../src/foment.hpp ../src/syncthrd.hpp ../src/io.hpp\
+	../src/unicode.hpp
 release/io.o: ../src/io.cpp ../src/foment.hpp ../src/syncthrd.hpp ../src/io.hpp\
 	../src/unicode.hpp
 release/write.o: ../src/write.cpp ../src/foment.hpp ../src/syncthrd.hpp ../src/io.hpp\
@@ -180,9 +187,6 @@ debug/%.o: %.cpp
 debug/%.o: ../src/%.cpp
 	$(CXX) $(CCDEBUG) -I ../src -o $@ $<
 
-debug/%.o: ../src/%.c
-	$(CC) $(CCDEBUG) -I ../src -o $@ $<
-
 debug/%.o: debug/%.cpp
 	$(CXX) $(CCDEBUG) -I ../src -o $@ $<
 
@@ -192,9 +196,6 @@ release/%.o: %.cpp
 release/%.o: ../src/%.cpp
 	$(CXX) $(CCRELEASE) -I ../src -o $@ $<
 
-release/%.o: ../src/%.c
-	$(CC) $(CCRELEASE) -I ../src -o $@ $<
-
 release/%.o: debug/%.cpp
 	$(CXX) $(CCRELEASE) -I ../src -o $@ $<
 
@@ -204,12 +205,14 @@ profile/%.o: %.cpp
 profile/%.o: ../src/%.cpp
 	$(CXX) $(CCPROFILE) -I ../src -o $@ $<
 
-profile/%.o: ../src/%.c
-	$(CC) $(CCPROFILE) -I ../src -o $@ $<
-
 profile/%.o: debug/%.cpp
 	$(CXX) $(CCPROFILE) -I ../src -o $@ $<
 
+debug/%: ../test/%.cpp
+	$(BUILD_CXX) $(CCDEBUG) -o debug/$*.o $<
+	$(BUILD_CXX) debug/$*.o -o $@
+
 debug/txt2cpp: ../src/txt2cpp.cpp
 	$(BUILD_CXX) $(CCDEBUG) ../src/txt2cpp.cpp -o debug/txt2cpp.o
 	$(BUILD_CXX) debug/txt2cpp.o -o debug/txt2cpp
+
diff --git a/windows/makefile b/windows/makefile
index 0579f7a..e8205f9 100644
--- a/windows/makefile
+++ b/windows/makefile
@@ -2,22 +2,25 @@
 # Foment
 #
 
+PATH = $(PATH);../windows/debug
+
 TEST_OPTIONS = --check-heap
 TEST_BUILD = debug
 
-CLDEBUG = /nologo /MD /W3 /Gm /EHsc /Zi /Od /c /Fodebug/ /DFOMENT_DEBUG /DFOMENT_WINDOWS
-CLRELEASE = /nologo /MD /W3 /Ox /Zi /GA /EHsc /Forelease/ /c /DFOMENT_WINDOWS
+CLDEBUG = /nologo /MD /W3 /EHsc /Zi /Od /c /Fodebug\ /DFOMENT_DEBUG /DFOMENT_WINDOWS
+CLRELEASE = /nologo /MD /W3 /Ox /Zi /GA /EHsc /Forelease\ /c /DFOMENT_WINDOWS
 
 LIBS = ws2_32.lib iphlpapi.lib
 
-all: debug release debug\foment.exe release\foment.exe
+all: debug release debug\foment.exe release\foment.exe debug\stdread.exe debug\stdwrite.exe\
+        debug\exitcode.exe debug\hang.exe
 
 clean: debug release manual
     del /Q debug\*
     del /Q release\*
     del /Q manual\*
 
-test: all foment-test stress-test chibi-test
+test: all foment-test stress-test chibi-test process-test
 
 test-all: all test-no-collector test-mark-sweep
 
@@ -53,6 +56,10 @@ chibi-test: all
     cd ..\test
     ..\windows\$(TEST_BUILD)\foment $(TEST_OPTIONS) runtests.scm stress.scm r7rs-tests.scm
 
+process-test: all
+    cd ..\test
+    ..\windows\$(TEST_BUILD)\foment $(TEST_OPTIONS) runtests.scm process.scm
+
 debug:
     -mkdir debug
 
@@ -74,7 +81,7 @@ debug\foment.exe: debug\foment.obj debug\gc.obj debug\syncthrd.obj debug\compile
         debug\pairs.obj debug\unicode.obj debug\chars.obj debug\strings.obj debug\vectors.obj\
         debug\library.obj debug\execute.obj debug\numbers.obj debug\write.obj\
         debug\read.obj debug\filesys.obj debug\compare.obj debug\main.obj debug\hashtbl.obj\
-        debug\bignums.obj debug\charset.obj debug\base.obj
+        debug\bignums.obj debug\charset.obj debug\process.obj debug\base.obj
     link /nologo /subsystem:console /out:debug\foment.exe /debug /pdb:debug\foment.pdb\
         /largeaddressaware $** $(LIBS)
 
@@ -84,14 +91,25 @@ release\foment.exe: release\foment.obj release\gc.obj release\syncthrd.obj relea
         release\strings.obj release\vectors.obj release\library.obj release\execute.obj\
         release\numbers.obj release\write.obj release\read.obj\
         release\filesys.obj release\compare.obj release\main.obj release\hashtbl.obj\
-        release\bignums.obj release\charset.obj release\base.obj
+        release\bignums.obj release\charset.obj release\process.obj release\base.obj
 #    link /nologo /subsystem:console /out:release\foment.exe $**
     link /nologo /subsystem:console /out:release\foment.exe /debug /pdb:release\foment.pdb\
         /largeaddressaware $** $(LIBS)
 
 debug\txt2cpp.exe: debug\txt2cpp.obj
-    link /nologo /subsystem:console /out:debug\txt2cpp.exe\
-    debug\txt2cpp.obj
+    link /nologo /subsystem:console /out:debug\txt2cpp.exe debug\txt2cpp.obj
+
+debug\stdread.exe: debug\stdread.obj
+    link /nologo /subsystem:console /out:debug\stdread.exe debug\stdread.obj
+
+debug\stdwrite.exe: debug\stdwrite.obj
+    link /nologo /subsystem:console /out:debug\stdwrite.exe debug\stdwrite.obj
+
+debug\exitcode.exe: debug\exitcode.obj
+    link /nologo /subsystem:console /out:debug\exitcode.exe debug\exitcode.obj
+
+debug\hang.exe: debug\hang.obj
+    link /nologo /subsystem:console /out:debug\hang.exe debug\hang.obj
 
 debug\foment.obj: ..\src\foment.cpp ..\src\foment.hpp ..\src\syncthrd.hpp ..\src\unicode.hpp
 debug\gc.obj: ..\src\gc.cpp ..\src\foment.hpp ..\src\syncthrd.hpp ..\src\io.hpp
@@ -111,6 +129,8 @@ debug\execute.obj: ..\src\execute.cpp ..\src\foment.hpp ..\src\execute.hpp ..\sr
 debug\numbers.obj: ..\src\numbers.cpp ..\src\foment.hpp ..\src\unicode.hpp ..\src\bignums.hpp
 debug\bignums.obj: ..\src\bignums.cpp ..\src\foment.hpp ..\src\unicode.hpp ..\src\bignums.hpp
 debug\charset.obj: ..\src\charset.cpp ..\src\foment.hpp ..\src\unicode.hpp  ..\src\unicrng.hpp
+debug\process.obj: ..\src\process.cpp ..\src\foment.hpp ..\src\syncthrd.hpp ..\src\io.hpp\
+    ..\src\unicode.hpp
 debug\io.obj: ..\src\io.cpp ..\src\foment.hpp ..\src\syncthrd.hpp ..\src\io.hpp ..\src\unicode.hpp
 debug\write.obj: ..\src\write.cpp ..\src\foment.hpp ..\src\syncthrd.hpp ..\src\io.hpp\
     ..\src\compile.hpp
@@ -140,6 +160,8 @@ release\execute.obj: ..\src\execute.cpp ..\src\foment.hpp ..\src\execute.hpp ..\
 release\numbers.obj: ..\src\numbers.cpp ..\src\foment.hpp ..\src\unicode.hpp ..\src\bignums.hpp
 release\bignums.obj: ..\src\bignums.cpp ..\src\foment.hpp ..\src\unicode.hpp ..\src\bignums.hpp
 release\charset.obj: ..\src\charset.cpp ..\src\foment.hpp ..\src\unicode.hpp  ..\src\unicrng.hpp
+release\process.obj: ..\src\process.cpp ..\src\foment.hpp ..\src\syncthrd.hpp ..\src\io.hpp\
+    ..\src\unicode.hpp
 release\io.obj: ..\src\io.cpp ..\src\foment.hpp ..\src\syncthrd.hpp ..\src\io.hpp\
     ..\src\unicode.hpp
 release\write.obj: ..\src\write.cpp ..\src\foment.hpp ..\src\syncthrd.hpp ..\src\io.hpp\
@@ -154,6 +176,11 @@ release\base.obj: debug\base.cpp
 
 debug\txt2cpp.obj: ..\src\txt2cpp.cpp
 
+debug\stdread.obj: ..\test\stdread.cpp
+debug\stdwrite.obj: ..\test\stdwrite.cpp
+debug\exitcode.obj: ..\test\exitcode.cpp
+debug\hang.obj: ..\test\hang.cpp
+
 {.}.cpp.{debug}.obj:
     cl $(CLDEBUG) $(*B).cpp
 
@@ -178,3 +205,5 @@ debug\txt2cpp.obj: ..\src\txt2cpp.cpp
 {debug\}.cpp.{release}.obj:
     cl $(CLRELEASE) debug\$(*B).cpp
 
+{..\test\}.cpp.{debug}.obj:
+    cl $(CLDEBUG) ..\test\$(*B).cpp