#include <unistd.h> int symlink(const char *name1, const char *name2);
The symlink() function creates a symbolic link name2 to the file name1. Either name may be an arbitrary pathname, the files need not be on the same file system, and name1 may be nonexistent.
The file to which the symbolic link points is used when an open(2) operation is performed on the link. A stat() operation performed on a symbolic link returns the linked-to file, while an lstat() operation returns information about the link itself. See stat(2). Unexpected results may occur when a symbolic link is made to a directory. To avoid confusion in applications, the readlink(2) call can be used to read the contents of a symbolic link.
Upon successful completion, 0 is returned. Otherwise, -1 is returned, errno is set to indicate the error, and the symbolic link is not made.
The symlink() function will fail if:
Search permission is denied for a component of the path prefix of name2.
The directory where the entry for the new symbolic link is being placed cannot be extended because the user's quota of disk blocks on that file system has been exhausted; the new symbolic link cannot be created because the user's quota of disk blocks on that file system has been exhausted; or the user's quota of inodes on the file system where the file is being created has been exhausted.
The file referred to by name2 already exists.
The name1 or name2 argument points to an illegal address.
An I/O error occurs while reading from or writing to the file system.
Too many symbolic links are encountered in translating name2.
The length of the name2 argument exceeds PATH_MAX, or the length of a name2 component exceeds NAME_MAX while _POSIX_NO_TRUNC is in effect.
A component of the path prefix of name2 does not exist.
The directory in which the entry for the new symbolic link is being placed cannot be extended because no space is left on the file system containing the directory; the new symbolic link cannot be created because no space is left on the file system which will contain the link; or there are no free inodes on the file system on which the file is being created.
The file system does not support symbolic links
A component of the path prefix of name2 is not a directory.
The file name2 would reside on a read-only file system.
See attributes(5) for descriptions of the following attributes: