Path to binary in C

Question

How can I get the path where the binary that is executing resides in a C program?

I'm looking for something similar to __FILE__ in ruby/perl/PHP (but of course, the __FILE__ macro in C is determined at compile time).

dirname(argv[0]) will give me what I want in all cases unless the binary is in the user's $PATH... then I do not get the information I want at all, but rather "" or "."

Answer 1

Totally non-portable Linux solution:

#include <stdio.h>
#include <unistd.h>

int main()
{
  char buffer[BUFSIZ];
  readlink("/proc/self/exe", buffer, BUFSIZ);
  printf("%s\n", buffer);
}

This uses the "/proc/self" trick, which points to the process that is running. That way it saves faffing about looking up the PID. Error handling left as an exercise to the wary.

Answer 2

The non-portable Windows solution:

WCHAR path[MAX_PATH];
GetModuleFileName(NULL, path, ARRAYSIZE(path));