futimes - 改变文件的一个相对的时间戳到一个目录文件描述符
int futimesat(int dirfd, const char *path, const struct timeval times);
The futimesat() system call operates in exactly the same way as utimes(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 utimes(2) for a relative pathname).
If the pathname given in 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 utimes(2)).
If the pathname given in pathname is absolute, then dirfd is ignored.
On success, futimesat() returns a 0. On error, -1 is returned and errno is set to indicate the error.
The same errors that occur for utimes(2) can also occur for futimesat(). The following additional errors can occur for futimesat():
|EBADF||dirfd is not a valid file descriptor.|
|ENOTDIR||pathname is a relative path and dirfd is a file descriptor referring to a file other than a directory.|
This system call is non-standard but is proposed for inclusion in a future revision of POSIX.1. A similar system call exists on Solaris.
If the path argument is NULL, then the glibc futimes() wrapper function updates the times for the file referred to by dirfd.
futimesat() was added to Linux in kernel 2.6.16.
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