OSF  —  Environment_Note_Added

NAME

unlink − Removes a directory entry

SYNOPSIS

int unlink (
const char ∗path );

PARAMETERS

pathSpecifies the directory entry to be removed. 

DESCRIPTION

The unlink() function removes the directory entry specified by the path parameter and, if the entry is a hard link, decrements the link count of the file referenced by the link. 

When all links to a file are removed and no process has the file open or mapped, all resources associated with the file are reclaimed, and the file is no longer accessible. If one or more processes have the file open or mapped when the last link is removed, the link will be removed before the unlink() function returns, but the removal of the file contents is postponed until all open or map references to the file are removed.  If the path parameter names a symbolic link, the symbolic link itself is removed. 

Removing a hard link to a directory requires superuser privilege. 

Upon successful completion, the unlink() function marks for update the st_ctime and st_mtime fields of the directory which contained the link.  If the file’s link count is not 0 (zero), the st_ctime field of the file is also marked for update. 

NOTES

AES Support Level:
Full use

RETURN VALUES

Upon successful completion, a value of 0 (zero) is returned. If the unlink() function fails, a value of -1 is returned, the named file is not changed, and errno is set to indicate the error. 

ERRORS

If the unlink() function fails, the named file is not unlinked and errno may be set to one of the following values:

[ENOENT]The named file does not exist or the path parameter points to an empty string. 

[EACCES]Search permission is denied for a component of the path prefix, or write permission is denied on the directory containing the link to be removed. 

[EPERM]The named file is a directory, and the calling process does not have superuser privilege. 

[EPERM]The S_ISVTX flag is set on the directory containing the file to be deleted, and the caller is not the file owner. 

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

[EROFS]The entry to be unlinked is part of a read-only file system. 

[EFAULT]The path parameter is an invalid address. 

[ELOOP]Too many links were encountered in translating path. 

[ENAMETOOLONG]
The length of the path parameter exceeds PATH_MAX or a pathname component is longer than NAME_MAX. 

[ENOTDIR]A component of the path prefix is not a directory. 

ENVIRONMENT NOTES

This section describes system features that are not generic to OSF/1 but that are provided in this OSF/1 implementation. 

System V Compatibility

Any attempt to unlink non-empty directories in the System V habitat will cause the unlink call to fail and set errno to ENOTEMPTY, even if the process has superuser privileges.  This error behavior is provided in the System V habitat to comply with the SVID-2 industry standard. 

RELATED INFORMATION

Functions: close(2), link(2), open(2), rmdir(2)

Commands: rm(1)