UNLINK(2) Linux Programmer's Manual UNLINK(2)
unlink - delete a name and possibly the file it refers to
int unlink(const char *pathname);
unlink() deletes a name from the filesystem. If that name was the last
link to a file and no processes have the file open the file is deleted
and the space it was using is made available for reuse.
If the name was the last link to a file but any processes still have
the file open the file will remain in existence until the last file
descriptor referring to it is closed.
If the name referred to a symbolic link the link is removed.
If the name referred to a socket, fifo or device the name for it is
removed but processes which have the object open may continue to use
On success, zero is returned. On error, -1 is returned, and errno is
EACCES Write access to the directory containing pathname is not allowed
for the process's effective UID, or one of the directories in
pathname did not allow search permission. (See also path_reso-
EBUSY (not on Linux)
The file pathname cannot be unlinked because it is being used by
the system or another process and the implementation considers
this an error.
EFAULT pathname points outside your accessible address space.
EIO An I/O error occurred.
EISDIR pathname refers to a directory. (This is the non-POSIX value
returned by Linux since 2.1.132.)
ELOOP Too many symbolic links were encountered in translating path-
pathname was too long.
ENOENT A component in pathname does not exist or is a dangling symbolic
link, or pathname is empty.
ENOMEM Insufficient kernel memory was available.
A component used as a directory in pathname is not, in fact, a
EPERM The system does not allow unlinking of directories, or unlinking
of directories requires privileges that the current process
doesn't have. (This is the POSIX prescribed error return; as
noted above, Linux returns EISDIR for this case.)
EPERM (Linux only)
The filesystem does not allow unlinking of files.
EPERM or EACCES
The directory containing pathname has the sticky bit (S_ISVTX)
set and the process's effective UID is neither the UID of the
file to be deleted nor that of the directory containing it, and
the process is not privileged (Linux: does not have the
EROFS pathname refers to a file on a read-only filesystem.
SVr4, 4.3BSD, POSIX.1-2001.
Infelicities in the protocol underlying NFS can cause the unexpected
disappearance of files which are still being used.
rm(1), chmod(2), link(2), mknod(2), open(2), path_resolution(2),
rename(2), rmdir(2), unlinkat(2), mkfifo(3), remove(3)
Linux 2.6.7 2004-06-23 UNLINK(2)