READLINK(P) POSIX Programmer's Manual READLINK(P)
NAME
readlink - read the contents of a symbolic link
SYNOPSIS
#include <unistd.h>
ssize_t readlink(const char *restrict path, char *restrict buf,
size_t bufsize);
DESCRIPTION
The readlink() function shall place the contents of the symbolic link referred to by path in the buffer buf which has size bufsize. If the
number of bytes in the symbolic link is less than bufsize, the contents of the remainder of buf are unspecified. If the buf argument is not
large enough to contain the link content, the first bufsize bytes shall be placed in buf.
If the value of bufsize is greater than {SSIZE_MAX}, the result is implementation-defined.
RETURN VALUE
Upon successful completion, readlink() shall return the count of bytes placed in the buffer. Otherwise, it shall return a value of -1,
leave the buffer unchanged, and set errno to indicate the error.
ERRORS
The readlink() function shall fail if:
EACCES Search permission is denied for a component of the path prefix of path.
EINVAL The path argument names a file that is not a symbolic link.
EIO An I/O error occurred while reading from the file system.
ELOOP A loop exists in symbolic links encountered during resolution of the path argument.
ENAMETOOLONG
The length of the path argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.
ENOENT A component of path does not name an existing file or path is an empty string.
ENOTDIR
A component of the path prefix is not a directory.
The readlink() function may fail if:
EACCES Read permission is denied for the directory.
ELOOP More than {SYMLOOP_MAX} symbolic links were encountered during resolution of the path argument.
ENAMETOOLONG
As a result of encountering a symbolic link in resolution of the path argument, the length of the substituted pathname string
exceeded {PATH_MAX}.
The following sections are informative.
EXAMPLES
Reading the Name of a Symbolic Link
The following example shows how to read the name of a symbolic link named /modules/pass1.
#include <unistd.h>
char buf[1024];
ssizet_t len;
...
if ((len = readlink("/modules/pass1", buf, sizeof(buf)-1)) != -1)
buf[len] = '