unlink(2) unlink(2)
NAME
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 sym-
bolic 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 refer-
enced 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 stctime
and stmtime fields of the parent directory. Also, if the file's link
count is not 0, the stctime field of the file will be marked for
update.
ERRORS
The following error code descriptions are function-specific. You will
find a general description in introprm2(2) or in errno(5).
The named file is unlinked unless one or more of the following apply:
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 file named by the path argument cannot be unlinked
because it is being used by the system or another pro-
cess and the implementation considers this an error, or
the file named by path is a named stream.
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unlink(2) unlink(2)
EFAULT path points outside the process' allocated address
space.
EINTR A signal was caught during the unlink() system call.
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 PATHMAX or the
length of a path component exceeds NAMEMAX.
ENOENT The named file does not exist or is a null pathname. The
user is not a superuser.
ENOTDIR A component of the path prefix is not a directory.
EPERM The file named by path is a directory, and either the
calling process does not have appropriate privileges, or
the implementation prohibits using unlink() on direc-
tories.
EPERM or EACCES
The SISVTX flag is set on the directory containing the
file referred to by the path argument and the caller is
not the file owner, nor is the caller the directory
owner, nor does the caller have appropriate privileges.
EROFS The directory entry to be unlinked is part of a read-
only file system.
ENOLINK path points to a remote machine and the link to that
machine is no longer active.
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 PATHMAX.
ETXTBSY The entry to be unlinked is the last link to a pure pro-
cedure file that is being executed.
APPLICATION USAGE
Applications should use rmdir() to remove a directory.
RESULT
Upon successful completion, a value of 0 is returned. Otherwise, a
value of -1 is returned and errno is set to indicate the error.
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unlink(2) unlink(2)
SEE ALSO
rm(1), close(2), link(2), open(2), rmdir(2), remove(3C), unistd(4).
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