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Minix/CD-ROM-2.0/MINIX/MANUALS/CAT2/PIPE.2

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+PIPE(2)                   Minix Programmer's Manual                    PIPE(2)
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+
+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.
+
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+
+
+4BSD                             August 26, 1985                             1
+
+
+
+PIPE(2)                   Minix Programmer's Manual                    PIPE(2)
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+
+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.
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+4BSD                             August 26, 1985                             2
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