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UNLINK(2) | System Calls Manual | UNLINK(2) |
NAME¶
unlink
,
unlinkat
—
remove directory entry
LIBRARY¶
Standard C Library (libc, -lc)SYNOPSIS¶
#include
<unistd.h>
int
unlink
(const
char *path);
int
unlinkat
(int
fd, const char
*path, int
flag);
DESCRIPTION¶
Theunlink
() system call removes the link
named by path from its directory and
decrements the link count of the file which was referenced by the link. If
that decrement reduces the link count of the file to zero, and no process has
the file open, then all resources associated with the file are reclaimed. If
one or more process have the file open when the last link is removed, the link
is removed, but the removal of the file is delayed until all references to it
have been closed. The path argument may not
be a directory.
The unlinkat
() system call is equivalent to
unlink
() or
rmdir
() except in the case where
path specifies a relative path. In this case
the directory entry to be removed is determined relative to the directory
associated with the file descriptor fd
instead of the current working directory.
The values for flag are constructed by a
bitwise-inclusive OR of flags from the following list, defined in
<fcntl.h>
:
AT_REMOVEDIR
- Remove the directory entry specified by fd and path as a directory, not a normal file.
unlinkat
() is passed the special value
AT_FDCWD
in the
fd parameter, the current working directory
is used and the behavior is identical to a call to
unlink or
rmdir respectively, depending on whether or
not the AT_REMOVEDIR
bit is set in flag.
RETURN VALUES¶
Theunlink
() function returns the
value 0 if successful; otherwise the value -1 is returned and
the global variable errno is set to indicate
the error.
ERRORS¶
Theunlink
() succeeds unless:
- [
ENOTDIR
] - A component of the path prefix is not a directory.
- [
EISDIR
] - The named file is a directory.
- [
ENAMETOOLONG
] - A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters.
- [
ENOENT
] - The named file does not exist.
- [
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.
- [
ELOOP
] - Too many symbolic links were encountered in translating the pathname.
- [
EPERM
] - The named file is a directory.
- [
EPERM
] - The named file has its immutable, undeletable or append-only flag set, see the chflags(2) manual page for more information.
- [
EPERM
] - The parent directory of the named file has its immutable or append-only flag set.
- [
EPERM
] - The directory containing the file is marked sticky, and neither the containing directory nor the file to be removed are owned by the effective user ID.
- [
EIO
] - An I/O error occurred while deleting the directory entry or deallocating the inode.
- [
EROFS
] - The named file resides on a read-only file system.
- [
EFAULT
] - The path argument points outside the process's allocated address space.
unlink
(), the
unlinkat
() may fail if:
- [
EBADF
] - The path argument does not specify an
absolute path and the fd argument is
neither
AT_FDCWD
nor a valid file descriptor open for searching. - [
ENOTEMPTY
] - The flag parameter has the
AT_REMOVEDIR
bit set and the path argument names a directory that is not an empty directory, or there are hard links to the directory other than dot or a single entry in dot-dot. - [
ENOTDIR
] - The flag parameter has the
AT_REMOVEDIR
bit set and path does not name a directory. - [
EINVAL
] - The value of the flag argument is not valid.
- [
ENOTDIR
] - The path argument is not an absolute path
and fd is neither
AT_FDCWD
nor a file descriptor associated with a directory.
SEE ALSO¶
chflags(2), close(2), link(2), rmdir(2), symlink(7)STANDARDS¶
Theunlinkat
() system call follows The Open
Group Extended API Set 2 specification.
HISTORY¶
Theunlink
() function appeared in
Version 6 AT&T UNIX. The
unlinkat
() system call appeared in
FreeBSD 8.0.
The unlink
() system call traditionally allows
the super-user to unlink directories which can damage the file system
integrity. This implementation no longer permits it.April 25, 2010 | Debian |