FD

Section: Devices and Network Interfaces (4)
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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.  

FILES

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

 

SEE ALSO

tty(4)  

HISTORY

The descriptor implementation Ud
 

Index

NAME
DESCRIPTION
FILES
SEE ALSO
HISTORY

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Time: 06:48:41 GMT, May 19, 2025