REALPATH(3C) Standard C Library Functions REALPATH(3C)

realpath - resolve pathname

#include <stdlib.h>
char *realpath(const char *restrict file_name,
     char *restrict resolved_name);
char *canonicalize_file_name(const char *path);

The realpath() function derives, from the pathname pointed to by file_name, an absolute pathname that names the same file, whose resolution does not involve ".", "..", or symbolic links. The generated pathname is stored as a null-terminated string, up to a maximum of {PATH_MAX} bytes (defined in limits.h(3HEAD)), in the buffer pointed to by resolved_name.

The canonicalize_file_name() function is equivalent to calling realpath(path, NULL). This function is only provided for compatibility.

On successful completion, realpath() returns a pointer to the resolved name. Otherwise, realpath() returns a null pointer and sets errno to indicate the error, and the contents of the buffer pointed to by resolved_name are left in an indeterminate state.

The realpath() function will fail if:


Read or search permission was denied for a component of file_name.


Either the file_name or resolved_name argument is a null pointer.


An error occurred while reading from the file system.


Too many symbolic links were encountered in resolving file_name.


A loop exists in symbolic links encountered during resolution of the file_name argument.


The file_name argument is longer than {PATH_MAX} or a pathname component is longer than {NAME_MAX}.


A component of file_name does not name an existing file or file_name points to an empty string.


A component of the path prefix is not a directory.

The realpath() function may fail if:


Pathname resolution of a symbolic link produced an intermediate result whose length exceeds {PATH_MAX}.


Insufficient storage space is available.

The realpath() function operates on null-terminated strings.

Execute permission is required for all the directories in the given and the resolved path.

The realpath() function might fail to return to the current directory if an error occurs.

See attributes(7) for descriptions of the following attributes:

Interface Stability Standard
MT-Level MT-Safe

getcwd(3C), sysconf(3C), limits.h(3HEAD), attributes(7), standards(7)
December 20, 2014 OmniOS