Manual of CANONICALIZE_FILE_NAME(3) (v2.18)

NAME

canonicalize_file_name - return the canonicalized filename

#define _GNU_SOURCE
#include <stdlib.h>

char *canonicalize_file_name (const char *path);

The call canonicalize_file_name(path) is equivalent to the call realpath(path, NULL).

The function is a GNU extension.