INVOCATION_NAME(3) Linux Programmer's Manual INVOCATION_NAME(3)

program_invocation_name, program_invocation_short_name - obtain name used to invoke calling program

#define _GNU_SOURCE         /* See feature_test_macros(7) */
#include <errno.h>
extern char *program_invocation_name;
extern char *program_invocation_short_name;

program_invocation_name contains the name that was used to invoke the calling program. This is the same as the value of argv[0] in main(), with the difference that the scope of program_invocation_name is global.
program_invocation_short_name contains the basename component of name that was used to invoke the calling program. That is, it is the same value as program_invocation_name, with all text up to and including the final slash (/), if any, removed.
These variables are automatically initialized by the glibc run-time startup code.

These variables are GNU extensions, and should not be used in programs intended to be portable.

The Linux-specific /proc/[number]/cmdline file provides access to similar information.

2017-09-15 GNU