REALPATH(3)                Library Functions Manual                REALPATH(3)

NAME
     realpath – returns the canonicalized absolute pathname

SYNOPSIS
     #include <stdlib.h>

     char *
     realpath(const char *restrict file_name, char *restrict resolved_name);

DESCRIPTION
     The realpath() function resolves all symbolic links, extra “/”
     characters, and references to /./ and /../ in file_name.  If the
     resolved_name argument is non-NULL, the resulting absolute pathname is
     copied there (it must refer to a buffer capable of storing at least
     PATH_MAX characters).

     As a permitted extension to the standard, if resolved_name is NULL,
     memory is allocated for the resulting absolute pathname, and is returned
     by realpath().  This memory should be freed by a call to free(3) when no
     longer needed.

     The realpath() function will resolve both absolute and relative paths and
     return the absolute pathname corresponding to file_name.  All components
     of file_name must exist when realpath() is called.

RETURN VALUES
     On success, the realpath() function returns the address of the resulting
     absolute pathname, which is resolved_name if it was non-NULL, or the
     address of newly allocated memory.  If an error occurs, realpath()
     returns NULL.  If resolved_name was non-NULL, it will contain the
     pathname which caused the problem.

VARIANTS
     Defining _DARWIN_C_SOURCE or _DARWIN_BETTER_REALPATH before including
     stdlib.h will cause the provided implementation of realpath() to use
     F_GETPATH from fcntl(2) to discover the path.

ERRORS
     The function realpath() may fail and set the external variable errno for
     any of the errors specified for the library functions alloca(3),
     getattrlist(2), getcwd(3), lstat(2), readlink(2), stat(2), and strdup(3).

LEGACY SYNOPSIS
     #include <sys/param.h>
     #include <stdlib.h>

     The include file <sys/param.h> is necessary.

LEGACY DESCRIPTION
     In legacy mode, the last component of file_name does not need to exist
     when realpath() is called.

SEE ALSO
     free(3), getcwd(3), compat(5)

HISTORY
     The realpath() function first appeared in 4.4BSD.

macOS 15.2                       April 5, 2008                      macOS 15.2