/dev/fd/#
stdout4
File descriptor files
Part of fd(4).
Overview
The files /dev/fd/0 through /dev/fd/# refer to file descriptors which can be accessed through the file system. If the file descriptor is open and the mode the file is being opened with is a subset of the mode of the existing descriptor, the call:
fd = open("/dev/fd/0", mode);
and the call:
fd = fcntl(0, F_DUPFD, 0);
are equivalent.
Opening the files /dev/stdin, /dev/stdout and /dev/stderr is equivalent to the following calls:
fd = fcntl(STDIN_FILENO, F_DUPFD, 0); fd = fcntl(STDOUT_FILENO, F_DUPFD, 0); fd = fcntl(STDERR_FILENO, F_DUPFD, 0);
Flags to the open(2) call other than O_RDONLY, O_WRONLY and O_RDWR are ignored.
Implementation notes
By default, /dev/fd is provided by devfs(4), which provides nodes for the first three file descriptors. Some sites may require nodes for additional file descriptors; these can be made available by mounting fdescfs(4) on /dev/fd.
Files
-
-
/dev/stdin -
/dev/stdout -
/dev/stderr
Releases
87 releases since FreeBSD 2.0.5-RELEASE; the text changed 42 times.