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.TH io_pipe 3
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.SH NAME
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io_pipe \- create a Unix pipe
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.SH SYNTAX
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.B #include <libowfat/io.h>
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int \fBio_pipe\fP(int64 pfd[2]);
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.SH DESCRIPTION
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io_pipe creates a new UNIX ``pipe.'' The pipe can receive data and provide
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data; any bytes written to the pipe can then be read from the pipe in the same
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order.
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A pipe is typically stored in an 8192-byte memory buffer; the exact number
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depends on the UNIX kernel. Bytes are written to the end of the buffer and read
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from the beginning of the buffer. Once a byte has been read, it is eliminated
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from the buffer, making space for another byte to be written; readers cannot
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``rewind'' a pipe to read old data. Once 8192 bytes have been written to the
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buffer, the pipe will not be ready for further writing until some of the bytes
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have been read. Once all the bytes written have been read, the pipe will not be
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ready for further reading until more bytes are written.
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io_pipe sets \fId\fR[0] to the number of a new descriptor reading from the pipe, and
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sets \fId\fR[1] to the number of a new descriptor writing to the pipe. It then
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returns 1 to indicate success. If something goes wrong, io_pipe returns 0,
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setting errno to indicate the error; in this case it frees any memory that it
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allocated for the new pipe, and it leaves \fId\fR alone.
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.SH "SEE ALSO"
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io_readfile(3), io_createfile(3), io_socketpair(3)
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