canonicalize_file_name - return the canonicalized absolute pathname

#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <stdlib.h>
char *canonicalize_file_name(const char *path);

The canonicalize_file_name() function returns a null-terminated string containing the canonicalized absolute pathname corresponding to path. In the returned string, symbolic links are resolved, as are . and .. pathname components. Consecutive slash (/) characters are replaced by a single slash.
The returned string is dynamically allocated by canonicalize_file_name() and the caller should deallocate it with free(3) when it is no longer required.
The call canonicalize_file_name(path) is equivalent to the call:

realpath(path, NULL);

On success, canonicalize_file_name() returns a null-terminated string. On error (e.g., a pathname component is unreadable or does not exist), canonicalize_file_name() returns NULL and sets errno to indicate the error.

See realpath(3).

For an explanation of the terms used in this section, see attributes(7).
Interface Attribute Value
canonicalize_file_name () Thread safety MT-Safe

This function is a GNU extension.

readlink(2), realpath(3)
2017-09-15 GNU