REALPATH(3) |
Library Functions Manual |
REALPATH(3) |
NAME
realpath — returns the canonicalized absolute pathname
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/param.h>
#include <stdlib.h>
char *
realpath(const char * restrict pathname, char * restrict resolvedname);
DESCRIPTION
The
realpath() function resolves all symbolic links, extra “/” characters and references to
/./ and
/../ in
pathname, and copies the resulting absolute pathname into the memory referenced by
resolvedname. The
resolvedname argument
must refer to a buffer capable of storing at least
MAXPATHLEN characters, or be
NULL.
The realpath() function will resolve both absolute and relative paths and return the absolute pathname corresponding to pathname.
RETURN VALUES
If
resolvedname is
NULL, it will be allocated and the returned pointer can be deallocated using
free(3). The
realpath() function returns
resolvedname on success. If an error occurs,
realpath() returns
NULL, and
resolvedname was not allocated by
realpath(), it will contain the pathname which caused the problem.
ERRORS
The function
realpath() may fail and set the external variable
errno for any of the errors specified for the library functions
lstat(2),
readlink(2),
getcwd(3) and
malloc(3).
In addition, the following errors may be reported:
-
[EINVAL]
-
The value of the pathname argument is NULL.
-
[ELOOP]
-
Too many symbolic links were encountered in translating the pathname.
-
[ENAMETOOLONG]
-
The resulting absolute pathname exceeds MAXPATHLEN characters.
-
[ENOENT]
-
The value of the pathname argument is an empty string; or a symbolic link to an empty string is encountered.
-
[ENOTDIR]
-
A component of the path prefix is not a directory.
STANDARDS
realpath() first appeared in X/Open Portability Guide Issue 4, Version 2 (“XPG4.2”) and is part of IEEE Std 1003.1-2001 (“POSIX.1”).
HISTORY
The realpath() function call first appeared in 4.4BSD. In NetBSD 7.0 the function was updated to accept a NULL pointer for the resolvedname argument.
BUGS
This implementation of realpath() differs slightly from the Solaris implementation. The 4.4BSD version always returns absolute pathnames, whereas the Solaris implementation will, under certain circumstances, return a relative resolvedname when given a relative pathname.