stdout.4freebsd

Langue: en

Version: 300265 (debian - 07/07/09)

Section: 4 (Pilotes et protocoles réseau)


BSD mandoc

NAME

fd stdin stdout stderr - file descriptor files

DESCRIPTION

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(5), 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(5) on /dev/fd

FILES

/dev/fd/#
/dev/stdin
/dev/stdout
/dev/stderr

SEE ALSO

tty(4), devfs(5), fdescfs(5)