UNLINK(2) BSD Programmer's Manual UNLINK(2)
unlink - remove directory entry
#include <unistd.h> int unlink(const char *path);
The unlink() function 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 processes have the file open when the last link is removed, the link is removed, but the removal of the file is de- layed until all references to it have been closed.
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.
The unlink() succeeds unless: [ENOTDIR] A component of the path prefix is not a directory. [ENAMETOOLONG] A component of a pathname exceeded {NAME_MAX} characters, or an entire path name exceeded {PATH_MAX} 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 and the effective user ID of the process is not the superuser, or the filesystem con- taining the file does not permit the use of unlink() on a directory. [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. [EPERM] The named file has its immutable or append-only flag set (see chflags(2)). [EBUSY] The entry to be unlinked is the mount point for a mounted filesystem. [EIO] An I/O error occurred while deleting the directory entry or deallocating the inode. [EROFS] The named file resides on a read-only filesystem. [EFAULT] path points outside the process's allocated address space.
close(2), link(2), rmdir(2), symlink(7)
An unlink() function call appeared in Version 2 AT&T UNIX. MirBSD #10-current June 4, 1993 1