The Tcl_FindExecutable procedure computes the full path name of
the executable file from which the application was invoked and saves
it for Tcls internal use.
The executables path name is needed for several purposes in
Tcl. For example, it is needed on some platforms in the
implementation of the load command.
It is also returned by the info nameofexecutable command.
On UNIX platforms this procedure is typically invoked as the very
first thing in the applications main program; it must be passed
argv as its argument. It is important not to change the
working directory before the invocation.
Tcl_FindExecutable uses argv0
along with the PATH environment variable to find the
applications executable, if possible. If it fails to find
the binary, then future calls to info nameofexecutable
will return an empty string.
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. NULL
is returned if the internal full path name has not been
computed or unknown.