int fchmodat(int dirfd, const char *path, mode_t mode ", int " flags );
The fchmodat() system call operates in exactly the same way as chmod(2), except for the differences described in this manual page.
If the pathname given in path is relative, then it is interpreted relative to the directory referred to by the file descriptor dirfd (rather than relative to the current working directory of the calling process, as is done by chmod(2) for a relative pathname).
If the pathname given in path is relative and dirfd is the special value AT_FDCWD, thenpath is interpreted relative to the current working directory of the calling process (likechmod(2)).
If the pathname given in path is absolute, then dirfd is ignored.
flags can either be 0, or include the following flag:
|AT_SYMLINK_NOFOLLOW||If path is a symbolic link, do not dereference it: instead operate on the link itself. This flag is not currently implemented.|
On success, fchmodat() returns 0. On error, -1 is returned and errno is set to indicate the error.
The same errors that occur for chmod(2) can also occur for fchmodat(). The following additional errors can occur for fchmodat():
|EBADF||dirfd is not a valid file descriptor.|
|EINVAL||Invalid flag specified in flags.|
|ENOTDIR||path is a relative path and dirfd is a file descriptor referring to a file other than a directory.|
|ENOTSUP||flags specified AT_SYMLINK_NOFOLLOW, which is not supported.|
See openat(2) for an explanation of the need for fchmodat().
This system call is non-standard but is proposed for inclusion in a future revision of POSIX.1.
fchmodat() was added to Linux in kernel 2.6.16.
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