readlink(2) [netbsd man page]
READLINK(2) BSD System Calls Manual READLINK(2) NAME
readlink -- read value of a symbolic link LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <unistd.h> ssize_t readlink(const char * restrict path, char * restrict buf, size_t bufsiz); DESCRIPTION
readlink() places the contents of the symbolic link path in the buffer buf, which has size bufsiz. readlink() does not append a NUL charac- ter to buf. RETURN VALUES
The call returns the count of characters placed in the buffer if it succeeds, or a -1 if an error occurs, placing the error code in the global variable errno. EXAMPLES
A typical use is illustrated in the following piece of code which reads the contents of a symbolic link named /symbolic/link and stores them as null-terminated string: #include <limits.h> #include <unistd.h> char buf[PATH_MAX]; ssize_t len; if ((len = readlink("/symbolic/link", buf, sizeof(buf)-1)) == -1) error handling; buf[len] = ' '; ERRORS
readlink() will fail if: [ENOTDIR] A component of the path prefix is not a directory. [ENAMETOOLONG] A component of a pathname exceeded {NAME_MAX} characters, or an entire path name exceeded {PATH_MAX} characters. [ENOENT] The named file does not exist. [EACCES] Search permission is denied for a component of the path prefix. [ELOOP] Too many symbolic links were encountered in translating the pathname. [EINVAL] The named file is not a symbolic link. [EIO] An I/O error occurred while reading from the file system. [EFAULT] buf extends outside the process's allocated address space. SEE ALSO
lstat(2), stat(2), symlink(2), symlink(7) STANDARDS
The readlink() function conforms to IEEE Std 1003.1-2001 (``POSIX.1''). HISTORY
The readlink() function appeared in 4.2BSD. The type returned was changed from int to ssize_t in NetBSD 2.1. BSD
May 11, 2004 BSD
Check Out this Related Man Page
READLINK(2) Linux Programmer's Manual READLINK(2) NAME
readlink - read value of a symbolic link SYNOPSIS
#include <unistd.h> ssize_t readlink(const char *path, char *buf, size_t bufsiz); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): readlink(): _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED || _POSIX_C_SOURCE >= 200112L DESCRIPTION
readlink() places the contents of the symbolic link path in the buffer buf, which has size bufsiz. readlink() does not append a null byte to buf. It will truncate the contents (to a length of bufsiz characters), in case the buffer is too small to hold all of the contents. RETURN VALUE
On success, readlink() returns the number of bytes placed in buf. On error, -1 is returned and errno is set to indicate the error. ERRORS
EACCES Search permission is denied for a component of the path prefix. (See also path_resolution(7).) EFAULT buf extends outside the process's allocated address space. EINVAL bufsiz is not positive. EINVAL The named file is not a symbolic link. EIO An I/O error occurred while reading from the file system. ELOOP Too many symbolic links were encountered in translating the pathname. ENAMETOOLONG A pathname, or a component of a pathname, was too long. ENOENT The named file does not exist. ENOMEM Insufficient kernel memory was available. ENOTDIR A component of the path prefix is not a directory. CONFORMING TO
4.4BSD (readlink() first appeared in 4.2BSD), POSIX.1-2001. NOTES
In versions of glibc up to and including glibc 2.4, the return type of readlink() was declared as int. Nowadays, the return type is declared as ssize_t, as (newly) required in POSIX.1-2001. SEE ALSO
lstat(2), readlinkat(2), stat(2), symlink(2), path_resolution(7), symlink(7) COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 2010-09-20 READLINK(2)