How to Write & Compile a Tcl Application as a Standalone C Program

Building a fully-compiled, standalone C program from Tcl/Tk and C code involves 3 basic steps:

1. Converting Tcl scripts into C strings (stored as character arrays and .c files);
2. Calling Tcl_VarEval() for each of these C strings;
3. Modifying the Tcl/Tk standard tkAppInit.c file.
   

4. Perform steps 1 and 2 above on the following "standard" .tcl files: init.tcl, tk.tcl, bgerror.tcl, button.tcl, entry.tcl, focus.tcl, listbox.tcl... (These scripts are part of the Tcl/Tk installation. If you define a widget with your own .tcl script, then exclude the standard script.)

5. Link the application with the static Tcl/Tk libraries; (e.g., use libtcl7.5.1.a and libtk4.1.a for Tcl version 7.5 and Tk version 4.1.)

The specifics given below are based on the source code and makefiles for sdr and confcntlr-v0.4. The .tcl files used in the explanation below are: uimain.tcl, ctrlmenu.tcl (from confcntlr-v0.4 source code), and libs.tcl (created by the Makefile).

1. Get a copy of Ron Frederick's "NetVideo Version 3.2 tcl2c.c"--this is available with the sdr and confcntlr source code.
   
2. Run all your Tcl files through tcl2c and give them a name such as "tcl_xxx"--e.g.,

   tcl2c tcl_uimain < uimain.tcl > tcl_uimain.c
   tcl2c tcl_ctrlmenu < ctrlmenu.tcl > tcl_ctrlmenu.c

3. Concatenate the standard .tcl files you will need, delete lines that source other .tcl scripts and perform the previous step.

UI_FILES = tcl_libs.o tcl_uimain.o tcl_ctrlmenu.o

TK_LIBRARY_FILES = $(LIBRARY_TCL)/init.tcl \
     $(LIBRARY_TK)/tk.tcl \
     $(LIBRARY_TK)/bgerror.tcl \
     $(LIBRARY_TK)/button.tcl \
     $(LIBRARY_TK)/entry.tcl \
     $(LIBRARY_TK)/focus.tcl \
     $(LIBRARY_TK)/listbox.tcl \
     $(LIBRARY_TK)/menu.tcl \
     $(LIBRARY_TK)/palette.tcl \
     $(LIBRARY_TK)/scale.tcl \
     $(LIBRARY_TK)/tearoff.tcl \
     $(LIBRARY_TK)/text.tcl \
     $(LIBRARY_TK)/optMenu.tcl $(LIBRARY_TK)/scrlbar.tcl

(I omitted ($LIBRARY_TK)/dialog.tcl because I wrote my own procedure.)

# Make a .c file from a .tcl file: use the .tcl file being processed
# ($<) as input to tcl2c but rename it so that the filename without
# the extension is used with "tcl_" prepended (tcl_$*)

tcl_%.c: %.tcl

rm -f $@; ./tcl2c tcl_$* < $< > $@

# Create the object files.

tcl_%.o: tcl_%.c

$(CC) -c $<

# Create the concatenated list of standard .tcl files and remove # lines with "source"; redirect the output to "libs.tcl".

libs.tcl: $(TK_LIBRARY_FILES)

cat $(TK_LIBRARY_FILES) | sed '/^[ ]*source[ ]/d' > libs.tcl

-- Declare global character arrays for each of the .c files created from .tcl files:

extern const char tcl_libs[], tcl_uimain[], tcl_ctrlmenu[];

static Tk_Window mainWin;
Tcl_Interp *interp;

delete the call: Tk_Main();

add this code:

#ifdef WIN32

    extern int TkPlatformInit(Tcl_Interp *interp);

    TkSetPlatformInit(TkPlatformInit);

#endif

add this code:

interp = Tcl_CreateInterp();

Tcl_AppInit(interp);

Tk_MainLoop();

delete the call to Tcl_Init;
KEEP THE CALL to Tk_Init()!
If not needed, delete the call to Tcl_StaticPackage();

add the following code:

mainWin = Tk_MainWindow(interp);

#ifdef WIN32

{

    extern int WinPutsCmd(ClientData, Tcl_Interp*, int, char **);

    Tcl_CreateCommand(interp,"puts",WinPutsCmd,0,0);

}

#endif

Add the Tcl_CreateCommand() statements for any Tcl commands that your C code will call.

Add: Tcl_VarEval(interp, tcl_libs, 0);
This will evaluate the TK_LIBRARY_FILES. Do NOT use Tcl_Eval().

Add: Tcl_Eval() or Tcl_VarEval() statements for each of the C strings created for your own Tcl scripts; e.g., Tcl_VarEval(interp, tcl_uimain, 0); Tcl_VarEval(interp, tcl_ctrlmenu, 0);

Copy the tkUnixInit.c file from the Tcl/Tk installation (or the file in the sdr or confcntlr source code). This has the TkPlatformInit() function. And, of course, include this file in your source code.