unlink.2

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 2 代码 · 共 99 行

.\" SCCSID: @(#)unlink.2	2.1	3/10/87
.TH unlink 2
.SH Name
unlink \- remove directory entry
.SH Syntax
.nf
.B unlink(\fIpath\fP)
.B char *\fIpath\fP;
.fi
.SH Description
.NXR "unlink system call"
.NXA "link system call" "unlink system call"
.NXR "file" "unlinking"
The
.PN unlink
system call removes the entry for the file
.I path
from its directory.
If this entry was the last link to the file,
and no process has the file open, then
all resources associated with the file are reclaimed.
If, however, the file was open in any process, the actual
resource reclamation is delayed until it is closed,
even though the directory entry has disappeared.
.SH Return Values
Upon successful completion, a value of 0 is returned.
Otherwise, a value of \-1 is returned, and
.I errno
is set to indicate the error.
.SH Diagnostics
The
.PN unlink 
system call succeeds unless:
.TP 15
[ENOTDIR]
A component of the \fIpath\fP prefix is not a directory.
.TP 15
[ENOENT]
The named file does not exist or
.I path
points to an empty string and the environment defined is POSIX or SYSTEM_FIVE.
.TP 15
[EACCES]
Search permission is denied for a component of the \fIpath\fP prefix.
.TP 15
[EACCES]
Write permission is denied on the directory containing the link
to be removed.
.TP 15
[EBUSY]
The entry to be unlinked is the mount point for a mounted file system.
.TP 15
[EROFS]
The named file resides on a read-only file system.
.TP 15
[EFAULT]
The
.I path
points outside the process's allocated address space.
.TP 15
[ELOOP]
Too many symbolic links were encountered in translating the pathname.
.TP 15
[ENAMETOOLONG]
A component of a pathname exceeded 255 characters, or an
entire pathname exceeded 1023 characters.
.TP 15
[EPERM]
The named file is a directory and the effective user ID
of the process is not the superuser.
.TP 15
[EPERM]
The named file is a directory and the environment
is defined is POSIX.
.TP 15
[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.
.TP 15
[EIO]
An I/O error occurred while deleting the directory entry or
deallocating the inode.
.TP
[ETIMEDOUT]
A connect request or remote file operation failed, because the connected party
did not properly respond after a period of time that is dependent on the
communications protocol.
.TP 15
[ETXTBSY]
The named file is the last link to a shared text
executable and the environment defined is POSIX or
SYSTEM_FIVE.
.SH Environment
Differs from the System V definition in that ELOOP
is a possible error condition.
.SH See Also
close(2), link(2), rmdir(2)