English
- PIPE(2) Minix Programmer's Manual PIPE(2)
- NAME
- pipe - create an interprocess communication channel
- SYNOPSIS
- #include <unistd.h>
- int pipe(int fildes[2])
- DESCRIPTION
- The pipe system call creates an I/O mechanism called a pipe. The file
- descriptors returned can be used in read and write operations. When the
- pipe is written using the descriptor fildes[1] up to PIPE_MAX bytes of
- data are buffered before the writing process is suspended. A read using
- the descriptor fildes[0] will pick up the data.
- PIPE_MAX equals 7168 under Minix, but note that most systems use 4096.
- It is assumed that after the pipe has been set up, two (or more)
- cooperating processes (created by subsequent fork calls) will pass data
- through the pipe with read and write calls.
- The shell has a syntax to set up a linear array of processes connected by
- pipes.
- Read calls on an empty pipe (no buffered data) with only one end (all
- write file descriptors closed) returns an end-of-file.
- The signal SIGPIPE is generated if a write on a pipe with only one end is
- attempted.
- RETURN VALUE
- The function value zero is returned if the pipe was created; -1 if an
- error occurred.
- ERRORS
- The pipe call will fail if:
- [EMFILE] Too many descriptors are active.
- [ENFILE] The system file table is full.
- [ENOSPC] The pipe file system (usually the root file system) has no
- free inodes.
- [EFAULT] The fildes buffer is in an invalid area of the process's
- address space.
- 4BSD August 26, 1985 1
- PIPE(2) Minix Programmer's Manual PIPE(2)
- SEE ALSO
- sh(1), read(2), write(2), fork(2).
- NOTES
- Writes may return ENOSPC errors if no pipe data can be buffered, because
- the pipe file system is full.
- BUGS
- Should more than PIPE_MAX bytes be necessary in any pipe among a loop of
- processes, deadlock will occur.
- 4BSD August 26, 1985 2
