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/**
* @file rtems/pipe.h
*
* This include file defines the interface to the POSIX FIFO/pipe file system
* support.
*/
/*
* Author: Wei Shen <cquark@gmail.com>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#ifndef _RTEMS_PIPE_H
#define _RTEMS_PIPE_H
#include <rtems/libio.h>
#ifdef __cplusplus
extern "C" {
#endif
/* Control block to manage each pipe */
typedef struct pipe_control {
char *Buffer;
unsigned int Size;
unsigned int Start;
unsigned int Length;
unsigned int Readers;
unsigned int Writers;
unsigned int waitingReaders;
unsigned int waitingWriters;
unsigned int readerCounter; /* incremental counters */
unsigned int writerCounter; /* for differentiation of successive opens */
rtems_id Semaphore;
rtems_id readBarrier; /* wait queues */
rtems_id writeBarrier;
#if 0
boolean Anonymous; /* anonymous pipe or FIFO */
#endif
} pipe_control_t;
/*
* Called by pipe() to create an anonymous pipe.
*/
extern int pipe_create(
int filsdes[2]
);
/*
* Interface to file system close.
*
* *pipep points to pipe control structure. When the last user releases pipe,
* it will be set to NULL.
*/
extern void pipe_release(
pipe_control_t **pipep,
rtems_libio_t *iop
);
/*
* Interface to file system open.
*
* *pipep points to pipe control structure. If called with *pipep = NULL,
* fifo_open will try allocating and initializing a control structure. If the
* call succeeds, *pipep will be set to address of new control structure.
*/
extern int fifo_open(
pipe_control_t **pipep,
rtems_libio_t *iop
);
/*
* Interface to file system read.
*/
extern ssize_t pipe_read(
pipe_control_t *pipe,
void *buffer,
size_t count,
rtems_libio_t *iop
);
/*
* Interface to file system write.
*/
extern ssize_t pipe_write(
pipe_control_t *pipe,
const void *buffer,
size_t count,
rtems_libio_t *iop
);
/*
* Interface to file system ioctl.
*/
extern int pipe_ioctl(
pipe_control_t *pipe,
uint32_t cmd,
void *buffer,
rtems_libio_t *iop
);
#ifdef __cplusplus
}
#endif
#endif
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