tcc4tcl (Tiny C Compiler for Tcl) is a Tcl extension that provides an interface to TCC.

It is a fork of tcltcc by Mark Janssen.

It is licensed under the terms of the LGPL v2.1 (or later).


Github mirror

SEH 20220618 -- In response to MiR's enhancements to TSP, which includes enhancements to tcc4tcl, I created a fork of this project in an effort to combine the multiple independent contributions made to it, and to upgrade the tinycc compiler used (0.9.26, released 2013) to the latest release (0.9.27, released 2017)

The repository was forked from cyan's fork [L1 ] of rkeene's repository.

A branch called "tcllab" was created from the commit representing the last official release (tcc4tcl 0.30) made by rkeene.

To the "tcllab" branch have been added enhancements contributed by MiR [L2 ].

Another branch called "upgrade_tcc_0_9_27" was created from the last official release commit to carry out the upgrade to tinycc 0.9.27. A bare-bones but functional upgrade has already been committed there.

The plan is to merge all enhancements into the "tcllab" branch, which will then be merged into the "master" branch as a new release. It will admittedly be a complex undertaking.

Compressed debug sections

AMG: gcc versions 5.1.0 and newer compress debug sections. tcc 0.9.26 does not know what to do with this. If libtcc1.a was produced with debug symbols using gcc 5.1.0 or newer, when tcc tries to initialize, it corrupts memory when applying symbol relocations to the debug sections in libtcc1.a. This is because the relocation table contains offsets into the uncompressed debug section. About half of these offsets will exceed the total size of the compressed debug section, which tcc operates on directly, not knowing it needs to decompress it first. tcc blindly trusts the symbol offsets and will happily scribble all over memory if it thinks that's what the relocation table says to do. The consequences are unpredictable. I had to use valgrind to see that this was the origin of my program's intermittent misbehavior, then it took a few days of high-powered sleuthing to track down the root cause.

The solution I've adopted is to ensure -gz=none is in CFLAGS when compiling tcc4tcl.

The solution recommended by the tcc team (for a different problem also documented on this page, but it would solve this problem too) is to change tcc4tcl to compile libtcc1.a using tcc rather than gcc.

tcc version

AMG: The current version of tcc4tcl (0.30) directly includes a patched copy of tcc 0.9.26 from early 2013. The most recent version of tcc is 0.9.27 from late 2017. I would very much like to upgrade to 0.9.27 because of the many improvements, but doing so breaks virtually all the tcc patches found in [L3 ].

Access to more symbols

AMG: The C code has access to Tcl and Tk symbols just fine, but other than that, the only available symbols are: printf, fprintf, fopen, and fclose. These are listed in tcc_syms in tccrun.c. It's clear that this list is present as only an example of how to add symbols.

I'm very much wishing for the ability to extend this list without editing the tcc source. In fact, many of the symbols I want to access may not even be available during the compilation and linking of tcc4tcl since they'll come from other dynamically loaded extension libraries. Mostly SQLite.

To do this, I extended the add_symbol command to allow dynamic symbol lookups, implemented using Tcl_LoadFile() or dlsym(), depending on context.

Tcl_LoadFile() is used when the symbol comes from a library. dlsym() is used when the symbol is baked into the interpreter (or is in a library loaded using [load -global]); however, this doesn't work in Windows.

Here's the patch against tcc4tcl version c1a5de894b [L4 ]. Warning: this patch contains tabs and end-of-line whitespace!

diff -ur tcc4tcl-0.30~/tcc4tcl.c tcc4tcl-0.30/tcc4tcl.c
--- tcc4tcl-0.30~/tcc4tcl.c        2019-06-11 12:25:16.849343862 -0500
+++ tcc4tcl-0.30/tcc4tcl.c        2019-06-11 19:34:35.721853441 -0500
@@ -19,6 +19,10 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#ifndef _WIN32
+#   include <dlfcn.h>
 #include <tcl.h>
 #include <stdlib.h>
 #include "tcc.h"
@@ -28,6 +32,9 @@
         int relocated;
+static Tcl_HashTable Tcc4tclHandles;
+static int Tcc4tclHandlesInitialized;
 static void Tcc4tclErrorFunc(Tcl_Interp * interp, char * msg) {
         Tcl_AppendResult(interp, msg, "\n", NULL);
@@ -58,6 +65,7 @@
 static int Tcc4tclHandleCmd ( ClientData cdata, Tcl_Interp *interp, int objc, Tcl_Obj * CONST objv[]){
         Tcl_WideInt val;
+        Tcl_Obj *expr_o;
         Tcl_Obj *val_o;
         void *val_p;
         int index;
@@ -127,27 +135,110 @@
                 tcc_add_library_path(s, Tcl_GetString(objv[2]));
                 return TCL_OK;
-        case TCC4TCL_ADD_SYMBOL:
-            if (objc != 4) {
-                Tcl_WrongNumArgs(interp, 2, objv, "symbol value");
+        case TCC4TCL_ADD_SYMBOL: {
+            Tcl_LoadHandle handle;
+            Tcl_HashEntry *entry;
+            static const char *const switches[] = {"-library", "-lookup", NULL};
+            enum {LIBRARY, LOOKUP} match;
+            Tcl_Obj *library = NULL;
+            const char *lookup[2] = {NULL, NULL};
+            int i;
+            int new;
+            if (objc < 3) {
+                Tcl_WrongNumArgs(interp, 2, objv, "symbol ?value? "
+                        "?-library libraryName? ?-lookup lookupName?");
                 return TCL_ERROR;
-            rv = Tcl_ExprObj(interp, Tcl_ObjPrintf("wide(%s)", Tcl_GetString(objv[3])), &val_o);
-            if (rv != TCL_OK) {
-                return TCL_ERROR;
+            /*
+             * [tcc add_symbol symbol value].  The value is the symbol address.
+             */
+            if (objc == 4) {
+                expr_o = Tcl_ObjPrintf("wide(%s)", Tcl_GetString(objv[3]));
+                rv = Tcl_ExprObj(interp, expr_o, &val_o);
+                Tcl_DecrRefCount(expr_o);
+                if (rv != TCL_OK) {
+                    return TCL_ERROR;
+                }
+                rv = Tcl_GetWideIntFromObj(interp, val_o, &val);
+                Tcl_DecrRefCount(val_o);
+                if (rv != TCL_OK) {
+                    return TCL_ERROR;
+                }
+                tcc_add_symbol(s, Tcl_GetString(objv[2]), (void *)val); 
+                return TCL_OK;
-            rv = Tcl_GetWideIntFromObj(interp, val_o, &val);
-            if (rv != TCL_OK) {
-                return TCL_ERROR;
+            /*
+             * [tcc add_symbol symbol ?-switches ...?].  Parse switches to
+             * obtain the library and lookup symbol names, if given.
+             */
+            lookup[0] = Tcl_GetString(objv[2]);
+            for (i = 3; i < objc; i += 2) {
+                if (Tcl_GetIndexFromObj(interp, objv[i], switches, "switch", 0,
+                        (int *)&match) != TCL_OK) {
+                    return TCL_ERROR;
+                } else if (i == objc - 1) {
+                    Tcl_Obj *error = Tcl_NewStringObj(
+                            "missing value for switch: ", -1);
+                    Tcl_AppendObjToObj(error, objv[i]);
+                    Tcl_SetObjResult(interp, error);
+                    return TCL_ERROR;
+                } else if (match == LIBRARY) {
+                    library = objv[i + 1];
+                } else if (match == LOOKUP) {
+                    lookup[0] = Tcl_GetString(objv[i + 1]);
+                }
-            val_p = (void *) val;
+            if (library) {
+                /*
+                 * -library was specified.  First, search the handle table for
+                 * the already-opened library.  If not found, open the library
+                 * and add it to the table, looking up the symbol as a side
+                 * effect.  If found, look up the symbol using the existing
+                 * handle.  In either case, fail if the symbol is missing.
+                 */
+                entry = Tcl_CreateHashEntry(&Tcc4tclHandles, library, &new);
+                if (new) {
+                    if (Tcl_LoadFile(interp, library, lookup, 0, &val_p,
+                            &handle) != TCL_OK) {
+                        Tcl_DeleteHashEntry(entry);
+                        return TCL_ERROR;
+                    }
+                    Tcl_SetHashValue(entry, handle);
+                } else if (!(val_p = Tcl_FindSymbol(interp,
+                        (Tcl_LoadHandle)Tcl_GetHashValue(entry), *lookup))) {
+                    return TCL_ERROR;
+                }
+            } else {
+                /*
+                 * -library was not specified.  If dlsym() is available, use
+                 * dlsym() to look up the symbol in the current process image.
+                 * This includes symbols statically and dynamically linked into
+                 * the current process (assuming they weren't marked "static";
+                 * be mindful of the double meaning of that word!), plus symbols
+                 * in libraries loaded by [load -global] or Tcl_LoadFile() using
+                 * the TCL_LOAD_GLOBAL flag.
+                 */
+#ifndef _WIN32
+                dlerror();
+                val_p = dlsym(RTLD_DEFAULT, Tcl_GetString(objv[objc - 1]));
+                if (!val_p && (str = dlerror())) {
+                    Tcl_SetResult(interp, str, TCL_VOLATILE);
+                    return TCL_ERROR;
+                }
+                Tcl_SetResult(interp, "-library required on this platform",
+                        TCL_STATIC);
+                return TCL_ERROR;
+            }
-            tcc_add_symbol(s,Tcl_GetString(objv[2]), val_p); 
+            tcc_add_symbol(s, Tcl_GetString(objv[2]), val_p); 
             return TCL_OK; 
-        case TCC4TCL_COMMAND:
+        } case TCC4TCL_COMMAND:
             if (objc != 4 && objc != 5) {
                 Tcl_WrongNumArgs(interp, 2, objv, "tclname cname ?clientData?");
                 return TCL_ERROR;
@@ -319,7 +410,29 @@
+        if (!Tcc4tclHandlesInitialized) {
+                Tcc4tclHandlesInitialized = 1;
+                Tcl_InitHashTable(&Tcc4tclHandles, TCL_STRING_KEYS);
+        }
         Tcl_CreateObjCommand(interp, "tcc4tcl", Tcc4tclCreateCmd, NULL, NULL);
         return TCL_OK;
+int Tcc4tcl_Unload(Tcl_Interp *interp, int flags) {
+        Tcl_HashSearch search;
+        Tcl_HashEntry *entry;
+        entry = Tcl_FirstHashEntry(&Tcc4tclHandles, &search);
+        while (entry) {
+            Tcl_FSUnloadFile(interp, (Tcl_LoadHandle)Tcl_GetHashValue(entry));
+            entry = Tcl_NextHashEntry(&search);
+        }
+        Tcl_DeleteHashTable(&Tcc4tclHandles);
+        Tcc4tclHandlesInitialized = 0;
+    }
+    return TCL_OK;
diff -ur tcc4tcl-0.30~/tcc4tcl.tcl tcc4tcl-0.30/tcc4tcl.tcl
--- tcc4tcl-0.30~/tcc4tcl.tcl        2019-06-11 12:25:16.850344362 -0500
+++ tcc4tcl-0.30/tcc4tcl.tcl        2019-06-11 13:54:07.764711760 -0500
@@ -46,7 +46,7 @@
-                array set $handle [list code "" type $type filename $output package $pkgName add_inc_path "" add_lib_path "" add_lib "" add_macros "" add_files ""]
+                array set $handle [list code "" type $type filename $output package $pkgName add_inc_path "" add_lib_path "" add_lib "" add_symbol "" add_macros "" add_files ""]
                 proc $handle {cmd args} [string map [list @@[email protected]@ $handle] {
                         set handle {@@[email protected]@}
@@ -63,7 +63,7 @@
                         set callcmd ::tcc4tcl::_$cmd
                         if {[info command $callcmd] == ""} {
-                                return -code error "unknown or ambiguous subcommand \"$cmd\": must be cwrap, ccode, cproc, ccommand, delete, linktclcommand, code, tk, add_include_path, add_library_path, add_library, process_command_line, or go"
+                                return -code error "unknown or ambiguous subcommand \"$cmd\": must be cwrap, ccode, cproc, ccommand, delete, linktclcommand, code, tk, add_include_path, add_library_path, add_library, add_symbol, process_command_line, or go"
                         uplevel 1 [list $callcmd $handle {*}$args]
@@ -118,6 +118,12 @@
                 lappend state(add_lib) {*}$args
+        proc _add_symbol {handle args} {
+                upvar #0 $handle state
+                lappend state(add_symbol) $args
+        }
         proc _add_file {handle args} {
                 upvar #0 $handle state
@@ -618,6 +624,10 @@
                         tcc add_file $addFile
+                foreach addSymbol $state(add_symbol) {
+                        tcc add_symbol {*}$addSymbol
+                }
                 switch -- $state(type) {
                         "memory" {
                                 tcc compile $code

  Simple testing
package require tcc4tcl
set tcc [tcc4tcl::new]
$tcc add_symbol sin
$tcc add_symbol cos
$tcc ccode {#include <math.h>}
$tcc cproc sin {double x} double {return sin(x);}
$tcc cproc cos {double x} double {return cos(x);}
$tcc go
sin [expr {asin(0.123)}]
cos [expr {acos(0.456)}]

  Complex testing
package require tcc4tcl
package require sqlite3
set tcc [tcc4tcl::new]
$tcc ccode {
#include "sqlite3.h"
testCmd(ClientData clientData, Tcl_Interp *interp,
int objc, Tcl_Obj *const objv[])
    sqlite3 *db;
    sqlite3_stmt *stmt;
    int rc;

    if ((rc = sqlite3_open_v2(NULL, &db, SQLITE_OPEN_READWRITE,
            NULL)) != SQLITE_OK) {
        Tcl_SetResult(interp, sqlite3_errstr(rc), TCL_VOLATILE);
        return TCL_ERROR;

    sqlite3_prepare_v2(db, "SELECT sqlite_version()", -1, &stmt, NULL);
    if (!stmt) {
        Tcl_SetResult(interp, sqlite3_errcode(db), TCL_VOLATILE);
        return TCL_ERROR;

    if (sqlite3_step(stmt) != SQLITE_ROW) {
        Tcl_SetResult(interp, sqlite3_errcode(db), TCL_VOLATILE);
        return TCL_ERROR;
    Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3_column_text(stmt, 0),
            sqlite3_column_bytes(stmt, 0)));

    if (sqlite3_finalize(stmt) != SQLITE_OK) {
        Tcl_SetResult(interp, sqlite3_errcode(db), TCL_VOLATILE);
        return TCL_ERROR;

    if ((rc = sqlite3_close(db)) != SQLITE_OK) {
        Tcl_SetResult(interp, sqlite3_errstr(rc), TCL_VOLATILE);
        return TCL_ERROR;

    return TCL_OK;
set lib [file join [info nameofexecutable] lib/sqlite3.28.0/]
$tcc add_symbol sqlite3_open_v2 -library $lib
$tcc add_symbol sqlite3_prepare_v2 -library $lib
$tcc add_symbol sqlite3_step -library $lib
$tcc add_symbol sqlite3_column_text -library $lib
$tcc add_symbol sqlite3_column_bytes -library $lib
$tcc add_symbol sqlite3_finalize -library $lib
$tcc add_symbol sqlite3_close -library $lib
$tcc add_symbol sqlite3_errstr -library $lib
$tcc add_symbol sqlite3_errcode -library $lib
$tcc linktclcommand test testCmd
$tcc go

This doesn't quite work on Windows. Not only is dlsym() missing, meaning that I can't find symbols already linked into the process, but the Tcl_LoadFile() approach is failing as well.

If I try to add symbols for a package that's already loaded, I get a permissions error. I'm guessing that Tcl_LoadFile() is trying to read the file a second time, yet Windows is locking it. Shouldn't Tcl_LoadFile() just point to the already-open library?

If I try to add symbols before loading the package, I get farther, but nevertheless all my symbol lookups fail. Maybe there need to be leading and/or trailing underscores. (That's what the -lookup switch is for, to allow the looked-up name to not match the name referenced within the C program.) However, these underscores don't show up in the output of nm, so I'm not sure that's really what's going on.

There's trouble on Linux too, at least in combination with VFS (tclkit) and sharing a database connection between Tcl and C . [package require sqlite3] invokes [load libsqlite3.*.so] which invokes Tcl_LoadFile() which is forced to copy libsqlite3.*.so to a temporary file to pass to dlopen(). Later on, [$tcc add_symbol sqlite3_* -library .../libsqlite3.*.so] calls Tcl_LoadFile() as well, not having access to the handle produced by the first call to dlopen(). Thus, SQLite is loaded twice, and the function pointers associated with the second are for code linked to a separate copy of all the static and global variables. This prevents sharing SQLite connections between Tcl and C, since Tcl and C are linked to separate copies of SQLite.

tclLoad.c actually does keep track of handles associated with already-loaded libraries, which can be looked up by package name ("Sqlite3" in this case). However, there is no API to access this table other than the unload command which has obvious and undesirable side effects.

The three solutions I can think of are:

  1. Statically link SQLite with the interpreter so the -library switch (therefore Tcl_LoadFile()) need not be used.
  2. Load SQLite using the -global switch to [load], so once again -library is not needed.
  3. Bypass [package require sqlite3] in favor of manually copying libsqlite3.*.so to a file tempfile file (guaranteed native filesystem), loading it, then passing that same file to tcc for its own symbol lookups, then finally deleting the file.

I've tried (3) and it works. The trouble with (1) is it's a change to the way my Tclkit is built, and office security procedures make it hard for me to publish new binaries (which by the way is a part of my motivation to integrate tcc). Both (1) and (2) seem to be fundamentally incompatible with Windows due to requiring dlsym(RTLD_DEFAULT).

32-bit Windows link failure

AMG: With tcc4tcl 0.30 (tcc 0.9.26) compiled with 32-bit MXE GCC 5.4.0, or with the official build [L5 ] (tried with [L6 ]), I get the following error:

% tcc4tcl::cproc test {Tcl_WideInt a int b} Tcl_WideInt {return a << b;}
tcc: error: undefined symbol '__ashldi3'
relocating failed

This is only a problem in Windows, not Linux. The cause is twofold. (1) gcc is prefixing all the symbol names in libtcc1.a with an extra underscore that tcc is not expecting, and (2) gcc is producing PE-format object files, and tcc only knows how to link ELF object files.

The solution is to apply this patch:

diff -ur tcc4tcl-0.30-old/ tcc4tcl-0.30-new/
--- tcc4tcl-0.30-old/        2017-10-13 15:37:05.000000000 -0500
+++ tcc4tcl-0.30-new/        2019-03-13 15:04:27.510092464 -0500
@@ -8,6 +8,8 @@
 CPP = @[email protected]
 AR = @[email protected]
 RANLIB = @[email protected]
+OBJCOPY = @[email protected]
+OBJDUMP = @[email protected]
 CFLAGS = @[email protected] @[email protected]
 CPPFLAGS = @[email protected] -I$(shell cd @[email protected] && pwd) -I$(shell cd @[email protected] && pwd)/tcc -I$(shell pwd)/tcc @[email protected] @[email protected]
 LDFLAGS = @[email protected]
@@ -29,7 +31,7 @@
 host_os = @[email protected]
 @[email protected]
-all: $(TARGET) tcc/libtcc1.a
+all: $(TARGET) tcc/libtcc1-elf.a
         if [ "$(srcdir)" = "." ]; then \
@@ -46,6 +48,17 @@
         -$(MAKE) -C tcc [email protected]@
         $(MAKE) -C tcc libtcc1.a
+# tcc supports dynamically loading object code from ELF, not from PE, so on some
+# platforms it is necessary to convert its runtime support library to ELF.
+tcc/libtcc1-elf.a: tcc/libtcc1.a
+        if $(OBJDUMP) -a $< | grep -q ' file format pei\?-x86-64$$'; then \
+                $(OBJCOPY) --remove-leading-char -O elf64-x86-64 $< [email protected]; \
+        elif $(OBJDUMP) -a $< | grep -q ' file format pei\?-i386$$'; then \
+                $(OBJCOPY) --remove-leading-char -O elf32-i386 $< [email protected]; \
+        else \
+                cp -f $< [email protected]; \
+        fi
 tcc4tcl.o: $(srcdir)/tcc4tcl.c $(srcdir)/tcc/tcc.h $(srcdir)/tcc/libtcc.h tcc/config.h
         $(CC) $(CPPFLAGS) $(CFLAGS) -o tcc4tcl.o -c $(srcdir)/tcc4tcl.c
@@ -60,7 +73,7 @@
         mv tcc4tcl-static.a
-install: $(TARGET) pkgIndex.tcl $(srcdir)/tcc4tcl.tcl $(srcdir)/tcc4critcl.tcl tcc/libtcc1.a $(shell echo $(srcdir)/tcc/include/*) $(shell echo $(srcdir)/tcc/win32/lib/*.c) $(srcdir)/headers.awk $(srcdir)/
+install: $(TARGET) pkgIndex.tcl $(srcdir)/tcc4tcl.tcl $(srcdir)/tcc4critcl.tcl tcc/libtcc1-elf.a $(shell echo $(srcdir)/tcc/include/*) $(shell echo $(srcdir)/tcc/win32/lib/*.c) $(srcdir)/headers.awk $(srcdir)/
         $(INSTALL) -d "$(DESTDIR)$(PACKAGE_INSTALL_DIR)/include"
@@ -68,7 +81,7 @@
         $(INSTALL) -m 0644 pkgIndex.tcl "$(DESTDIR)$(PACKAGE_INSTALL_DIR)"
         $(INSTALL) -m 0644 $(srcdir)/tcc4tcl.tcl "$(DESTDIR)$(PACKAGE_INSTALL_DIR)"
         $(INSTALL) -m 0644 $(srcdir)/tcc4critcl.tcl "$(DESTDIR)$(PACKAGE_INSTALL_DIR)"
-        $(INSTALL) -m 0644 tcc/libtcc1.a "$(DESTDIR)$(PACKAGE_INSTALL_DIR)/lib"
+        $(INSTALL) -m 0644 tcc/libtcc1-elf.a "$(DESTDIR)$(PACKAGE_INSTALL_DIR)/lib/libtcc1.a"
         $(INSTALL) -m 0644 $(shell echo $(srcdir)/tcc/win32/lib/*.c) "$(DESTDIR)$(PACKAGE_INSTALL_DIR)/lib"
         $(INSTALL) -m 0644 $(shell echo $(srcdir)/tcc/include/*) "$(DESTDIR)$(PACKAGE_INSTALL_DIR)/include"
         @if ! echo "_WIN32" | $(CPP) $(CPPFLAGS) - | grep '^_WIN32$$' >/dev/null; then \
diff -ur tcc4tcl-0.30-old/ tcc4tcl-0.30-new/
--- tcc4tcl-0.30-old/        2017-10-13 15:37:16.000000000 -0500
+++ tcc4tcl-0.30-new/        2019-03-13 15:06:59.156101031 -0500
@@ -39,6 +39,7 @@
+AC_CHECK_TOOL([OBJDUMP], [objdump])
diff -ur tcc4tcl-0.30-old/test.tcl tcc4tcl-0.30-new/test.tcl
--- tcc4tcl-0.30-old/test.tcl        2017-10-13 15:37:05.000000000 -0500
+++ tcc4tcl-0.30-new/test.tcl        2019-03-13 15:09:06.231108210 -0500
@@ -15,6 +15,9 @@
 # This should work
 tcc4tcl::cproc test3 {int i} int { return(i+42); }
+# Check for libtcc1 functionality
+tcc4tcl::cproc testlibtcc1 {double x} int { return(x); }
 # Multiple arguments
 tcc4tcl::cproc add {int a int b} int { return(a+b); }

Be cautious with this patch since it intentionally contains tabs and end-of-line whitespace, all of which have been stripped off by the wiki. Let me know if you want the original file with correct formatting.

After applying the patch, run "autoconf" to regenerate the configure script.

I have confirmed that the above patch fixes 32-bit Windows and does not break 64-bit Windows, 32-bit Linux, or 64-bit Linux.

Note: Even though I say that the error only happens on 32-bit Windows, as far as I can tell, this is only because libtcc1 is not needed as much on 64-bit Windows. If I dug deeper, I could probably find a test case that would break 64-bit Windows too, i.e. a case where libtcc1 is used on both 32- and 64-bit CPUs.

Variadic arguments

AMG: Is there any facility to access a cproc command's full objv argument list?

Answer: No. Bypass cproc and instead use ccode directly to create functions matching the signature shown below. Then use linktclcommand to arrange for Tcl_CreateObjCommand to be called on those functions. Note that the created Tcl commands are in the global namespace by default, not in the current namespace eval namespace, unless the namespace is explicitly given in the command name.

typedef int Tcl_ObjCmdProc(
        ClientData clientData,
        Tcl_Interp *interp,
        int objc,
        Tcl_Obj *const objv[]);


dbohdan 2015-03-16: As of version 0.23 you can compile tcc4tcl on Linux thus:

set -e
curl "$url" -o "${release}.tar.gz" # -O may not be unavailable.
tar zxvf "$release.tar.gz"
cd $release

dbohdan: Updated the script once more to hammer Roy Keene's server less.