FCHMODATSection: Linux Programmer's Manual (2)
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NAMEfchmodat - change permissions of a file relative to a directory file descriptor
#define _ATFILE_SOURCE #include <sys/stat.h> int fchmodat(int dirfd, const char *pathname, mode_t mode, int flags);
DESCRIPTIONThe 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 pathname 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 pathname is relative and dirfd is the special value AT_FDCWD, then pathname is interpreted relative to the current working directory of the calling process (like chmod(2)).
If pathname is absolute, then dirfd is ignored.
flags can either be 0, or include the following flag:
- If pathname is a symbolic link, do not dereference it: instead operate on the link itself. This flag is not currently implemented.
RETURN VALUEOn success, fchmodat() returns 0. On error, -1 is returned and errno is set to indicate the error.
ERRORSThe same errors that occur for chmod(2) can also occur for fchmodat(). The following additional errors can occur for fchmodat():
- dirfd is not a valid file descriptor.
- Invalid flag specified in flags.
- pathname is relative and dirfd is a file descriptor referring to a file other than a directory.
- flags specified AT_SYMLINK_NOFOLLOW, which is not supported.
VERSIONSfchmodat() was added to Linux in kernel 2.6.16.
CONFORMING TOThis system call is non-standard but is proposed for inclusion in a future revision of POSIX.1.
NOTESSee openat(2) for an explanation of the need for fchmodat().
SEE ALSOchmod(2), openat(2), path_resolution(7)