GETPROGNAME(3)

NAME
getprogname, setprogname - get or set the program name

LIBRARY
libc

SYNOPSIS
#include <stdlib.h>
const char *
getprogname(void);
void
setprogname(const char *progname);

DESCRIPTION
The getprogname() and setprogname() functions manipulate the name of the current program. They are used by error-reporting routines to produce consistent output.

The getprogname() function returns the name of the program. If the name has not been set yet, it will return NULL.

The setprogname() function sets the name of the program to be the last component of the progname argument. Since a pointer to the given string is kept as the program name, it should not be modified for the rest of the program's lifetime.

In FreeBSD, the name of the program is set by the start-up code that is run before main(); thus, running setprogname() is not necessary. Programs that desire maximum portability should still call it; on another operating system, these functions may be implemented in a portability library. Calling setprogname() allows the aforementioned library to learn the program name without modifications to the start-up code.

EXAMPLES
The following example presents a simple program, which shows the difference between getprogname() and argv[0].

    #include <stdio.h>
    #include <stdlib.h>
    int
    main(int argc, char** argv)
    {
    	printf("getprogname(): %s\n", getprogname());
    	printf("argv[0]: %s\n", argv[0]);
    	return (0);
    }

When compiled and executed (e.g., with ‘./a.out’) the output of the program is going to look like this:

    getprogname(): a.out
    argv[0]: ./a.out

SEE ALSO
err(3), setproctitle(3)

HISTORY
These functions first appeared in NetBSD 1.6, and made their way into FreeBSD 4.4.