int
pipe(
int fildes[2]
)
)
function
creates a
pipe,
which is an object allowing
unidirectional data flow,
and allocates a pair of file descriptors.
The first descriptor connects to the
read end
of the pipe,
and the second connects to the
write end,
so that data written to
fildes[1]
appears on (i.e., can be read from)
fildes[0]
.
This allows the output of one program to be
sent
to another program:
the source's standard output is set up to be
the write end of the pipe,
and the sink's standard input is set up to be
the read end of the pipe.
The pipe itself persists until all its associated descriptors are
closed.
A pipe whose read or write end has been closed is considered
widowed.
Writing on such a pipe causes the writing process to receive
a
SIGPIPE
signal.
Widowing a pipe is the only way to deliver end-of-file to a reader:
after the reader consumes any buffered data, reading a widowed pipe
returns a zero count.
)
call will fail if:
EMFILE
]
ENFILE
]
EFAULT
]
fildes
buffer is in an invalid area of the process's address space.
The reliable detection of this error cannot be guaranteed; when not
detected, a signal may be delivered to the process, indicating an
address violation.
)
function conforms to
ISO/IEC 9945-1:1990 (``POSIX.1'') .
)
function call appeared in
Version 6 AT&T UNIX
.