Tcl_FindExecutable(3tcl)

💖 Tcl_FindExecutable — bestie edition 💖

okay so this is the Tcl_FindExecutable / Tcl_GetNameOfExecutable manual page from the Tcl library procedures, and it's literally about figuring out which binary file you are — like the executable's whole personality, its full path, where it lives. 🦋 identifying or returning the name of the binary file containing the application, periodt.

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✨ SYNOPSIS ✨

#include <tcl.h>

const char *
Tcl_FindExecutable(argv0)

const char *
Tcl_GetNameOfExecutable()

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🌸 ARGUMENTS 🌸

• char *argv0 (in) — the first command-line argument to the program, aka the thing that tells you the application's name. the OG argv[0]. no cap.

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💅 DESCRIPTION 💅

so Tcl_FindExecutable computes the full path name of the executable file that your application was invoked from, and then saves it for Tcl's internal use. it's giving "let me find myself" ✨. and the reason Tcl needs that path name at all? several purposes, bestie. for example, on some platforms it's needed for the implementation of the load command. it's also the thing returned by the info nameofexecutable command.

the result of Tcl_FindExecutable is the full Tcl version with build information — like, for real, something shaped like:

9.0.0+abcdef...abcdef.gcc-1002

🐧 On UNIX platforms

this procedure is typically invoked as the very first thing in the application's main program — like, main character energy, it goes first. it must be passed argv[0] as its argument.

⚠️ it is important not to change the working directory before the invocation. do not do it. i'm serious. 🙈

Tcl_FindExecutable uses argv0 along with the PATH environment variable to find the application's executable, if possible. and if it fails to find the binary? then future calls to info nameofexecutable will return an empty string. empty. nothing. a whole void. 💀

🪟 On Windows platforms

this procedure is typically invoked as the very first thing in the application's main program as well. BUT — plot twist — its argv0 argument is only used to indicate whether the executable has a stderr channel (any non-null value) or not (the value null).

and here's why that matters: if Tcl_SetPanicProc is never called and no debugger is running, this determines whether the panic message is sent to stderr or to a standard system dialog. so like... pop-up or terminal, pick your fighter 🎀

🔍 Tcl_GetNameOfExecutable

Tcl_GetNameOfExecutable simply returns a pointer to the internal full path name of the executable file, as computed by Tcl_FindExecutable. this procedure call is the C API equivalent to the info nameofexecutable command. iykyk. ✨

and NULL is returned if the internal full path name has not been computed, or if it's unknown. so always check, bestie 🫶

🚨 real talk: Tcl_FindExecutable can not be used in stub-enabled extensions. that's just the rules. periodt.

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🔑 KEYWORDS 🔑

• binary
• executable file

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okay that's the whole vibe 🌈 — this page is Tcl_FindExecutable(3tcl) from the Tcl Library Procedures, dated way back in 8.1, and it's a Tcl situation through and through. go forth and find your executable, queen 👑💖