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Manual page for unlink(2)

unlink - remove directory entry

SYNOPSIS

#include <unistd.h>

int unlink(const char *path);

DESCRIPTION

The unlink() function removes a link to a file. If path names a symbolic link, unlink() removes the symbolic link named by path and does not affect any file or directory named by the contents of the symbolic link. Otherwise, unlink() removes the link named by the pathname pointed to by path and decrements the link count of the file referenced by the link.

When the file's link count becomes 0 and no process has the file open, the space occupied by the file will be freed and the file will no longer be accessible. If one or more processes have the file open when the last link is removed, the link will be removed before unlink() returns, but the removal of the file contents will be postponed until all references to the file are closed.

The path argument must not name a directory unless the process has appropriate privileges and the implementation supports using unlink() on directories.

Upon successful completion, unlink() will mark for update the st_ctime and st_mtime fields of the parent directory. Also, if the file's link count is not 0, the st_ctime field of the file will be marked for update.

RETURN VALUES

Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

The unlink() function will fail and not unlink the file if:

EACCES: Search permission is denied for a component of the path prefix.
EACCES: Write permission is denied on the directory containing the link to be removed.
EACCES: The parent directory has the sticky bit set and the file is not writable by the user; the user does not own the parent directory and the user does not own the file.
EBUSY: The entry to be unlinked is the mount point for a mounted file system.
EFAULT: path points to an illegal address.
EINTR: A signal was caught during the unlink() function.
ELOOP: Too many symbolic links were encountered in translating path.
EMULTIHOP: Components of path require hopping to multiple remote machines and the file system does not allow it.
ENAMETOOLONG: The length of the path argument exceeds {PATH_MAX}, or the length of a path component exceeds {NAME_MAX} while {_POSIX_NO_TRUNC} is in effect.
ENOENT: The named file does not exist or is a null pathname.
ENOLINK: path points to a remote machine and the link to that machine is no longer active.
ENOTDIR: A component of the path prefix is not a directory.
EPERM: The named file is a directory and the effective user of the calling process is not super-user.
EROFS: The directory entry to be unlinked is part of a read-only file system.

The unlink() function may fail and not unlink the file if:

ENAMETOOLONG: Pathname resolution of a symbolic link produced an intermediate result whose length exceeds PATH_MAX.
ETXTBSY: The entry to be unlinked is the last directory entry to a pure procedure (shared text) file that is being executed.

USAGE

Applications should use rmdir.2 to remove a directory.

ATTRIBUTES

See attributes.5 for descriptions of the following attributes:

+---------------+-------------------+
|ATTRIBUTE TYPE |  ATTRIBUTE VALUE  |
+---------------+-------------------+
|MT-Level       | Async-Signal-Safe |
+---------------+-------------------+