Jump to content United States-English
HP.com Home Products and Services Support and Drivers Solutions How to Buy
» Contact HP
More options
HP.com home
HP-UX Reference > U

unlink(2)

HP-UX 11i Version 3: February 2007
» 

Technical documentation

» Feedback
Content starts here

 » Table of Contents

 » Index

NAME

unlink — remove directory entry; delete file

SYNOPSIS

#include <unistd.h>

int unlink(const char *path);

DESCRIPTION

The unlink() system call removes the directory entry named by the path name pointed to by path.

When all links to a file have been removed and no process has the file open, the space occupied by the file is freed and the file ceases to exist. If one or more processes have the file open when the last link is removed, only the directory entry is removed immediately so that processes that do not already have the file open cannot access the file. After all processes close their references to the file, if there are no more links to the file, the space occupied by the file is then freed and the file ceases to exist.

RETURN VALUE

unlink() returns the following values:

0

Successful completion.

-1

Failure. errno is set to indicate the error.

ERRORS

If unlink() fails, errno is set to one of the following values:

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 process does not have read/write access permission to the parent directory.

EBUSY

The entry to be unlinked is the mount point for a mounted file system.

EFAULT

path points outside the process's allocated address space. The reliable detection of this error is implementation dependent.

ELOOP

Too many symbolic links were encountered in translating the path name.

ENAMETOOLONG

The length of the specified path name exceeds PATH_MAX bytes, or the length of a component of the path name exceeds NAME_MAX bytes while _POSIX_NO_TRUNC is in effect.

ENOENT

The named file does not exist (for example, path is null or a component of path does not exist).

ENOTDIR

A component of the path prefix is not a directory.

EPERM

The directory containing the file to be removed has the sticky bit set and neither the containing directory nor the file to be removed are owned by the effective user ID.

EPERM

The named file is a directory and the effective user ID is not a user with appropriate privileges. Some file systems return this error whenever the named file is a directory, regardless of the user ID.

EROFS

The directory entry to be unlinked is part of a read-only file system.

ETXTBSY

The entry to be unlinked is the last link to a pure procedure (shared text) file that is being executed.

WARNINGS

If unlink() is used on a directory that is not empty (contains files other than . and ..), the directory is unlinked, the files become orphans, and the directory link count is left with an inaccurate value unless they are linked by some other directory.

If unlink() is used on a directory that is empty (contains only the files . and ..), the directory is unlinked, but the parent directory's link count is left with an inaccurate value.

In either of the above cases, the file system should be checked using fsck (see fsck(1M)). To avoid these types of problems, use rmdir() instead (see rmdir(2)).

STANDARDS CONFORMANCE

unlink(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1

Printable version
Privacy statement Using this site means you accept its terms Feedback to webmaster
© 1983-2007 Hewlett-Packard Development Company, L.P.