NAME
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pipe – create an interprocess channel |
SYNOPSIS
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#include <u.h> #include <libc.h>
int pipe(int fd[2]) |
DESCRIPTION
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Pipe creates a buffered channel for interprocess I/O communication.
Two file descriptors are returned in fd. Data written to fd[1]
is available for reading from fd[0] and data written to fd[0]
is available for reading from fd[1]. After the pipe has been established, cooperating processes created by subsequent fork(2) calls may pass data through the pipe with read and write calls. The bytes placed on a pipe by one write are contiguous even if many processes are writing. Write boundaries are preserved: each read terminates when the read buffer is full or after reading the last byte of a write, whichever comes first. The number of bytes available to a read(2) is reported in the Length field returned by fstat or dirfstat on a pipe (see stat(2)).
When all the data has been read from a pipe and the writer has
closed the pipe or exited, read(2) will return 0 bytes. Writes
to a pipe with no reader will generate a note sys: write on closed
pipe. |
SOURCE
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/sys/src/libc/9syscall |
SEE ALSO
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intro(2), read(2), pipe(3) |
DIAGNOSTICS
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Sets errstr. |
BUGS
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If a read or a write of a pipe is interrupted, some unknown number
of bytes may have been transferred. When a read from a pipe returns 0 bytes, it usually means end of file but is indistinguishable from reading the result of an explicit write of zero bytes. |