source: rtems/cpukit/posix/include/aio.h @ 3cf4031

/**
 * @file
 *
 * @brief POSIX Asynchronous Input and Output
 * 
 * This file contains the definitions related to POSIX Asynchronous
 * Input and Output,
 */

/*
 *  COPYRIGHT (c) 1989-2011.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  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.
 */

#ifndef _AIO_H
#define _AIO_H

#include <unistd.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @defgroup POSIX_AIO POSIX Asynchronous I/O Support
 *
 * @ingroup POSIX
 *
 * @brief POSIX Asynchronous Input and Output
 */

#if defined(_POSIX_ASYNCHRONOUS_IO)

/*
 *  6.7.1 Data Definitions for Asynchronous Input and Output,
 *        P1003.1b-1993, p. 151
 */

#include <sys/types.h>
#include <signal.h>
#include <time.h>
#include <fcntl.h>

/*
 *  6.7.1.2 Manifest Constants, P1003.1b-1993, p. 153
 */

#define AIO_CANCELED    0 /* all requested operations have been canceled */
#define AIO_NOTCANCELED 1 /* some of the operations could not be canceled */
                          /*   since they are in progress */
#define AIO_ALLDONE     2 /* none of the requested operations could be */
                          /*   canceled since they are already complete */

/* lio_listio() options */

/*
 * LIO modes
 */
#define LIO_WAIT        0 /* calling process is to suspend until the */
                          /*   operation is complete */
#define LIO_NOWAIT      1 /* calling process is to continue execution while */
                          /*   the operation is performed and no notification */
                          /*   shall be given when the operation is completed */

/*
 * LIO opcodes
 */
#define LIO_NOP         0 /* no transfer is requested */
#define LIO_READ        1 /* request a read() */
#define LIO_WRITE       2 /* request a write() */
#define LIO_SYNC        3 /* needed by aio_fsync() */

/*
 *  6.7.1.1 Asynchronous I/O Control Block, P1003.1b-1993, p. 151
 */

struct aiocb {
  /* public */
  int             aio_fildes;     /* File descriptor */
  off_t           aio_offset;     /* File offset */
  volatile void  *aio_buf;        /* Location of buffer */
  size_t          aio_nbytes;     /* Length of transfer */
  int             aio_reqprio;    /* Request priority offset */
  struct sigevent aio_sigevent;   /* Signal number and value */
  int             aio_lio_opcode; /* Operation to be performed */
  /* private */
  int             error_code;      /* Used for aio_error() */
  ssize_t         return_value;     /* Used for aio_return() */
};

/*
 *  6.7.2 Asynchronous Read, P1003.1b-1993, p. 154
 */

int aio_read(
  struct aiocb  *aiocbp
);

/*
 *  6.7.3 Asynchronous Write, P1003.1b-1993, p. 155
 */

int aio_write(
  struct aiocb  *aiocbp
);

/*
 *  6.7.4 List Directed I/O, P1003.1b-1993, p. 158
 */

int lio_listio(
  int                    mode,
  struct aiocb  * const  list[],
  int                    nent,
  struct sigevent       *sig
);

/*
 *  6.7.5 Retrieve Error of Asynchronous I/O Operation, P1003.1b-1993, p. 161
 */

int aio_error(
  const struct aiocb  *aiocbp
);

/*
 *  6.7.6 Retrieve Return Status of Asynchronous I/O Operation,
 *        P1003.1b-1993, p. 162
 */

ssize_t aio_return(
  const struct aiocb  *aiocbp
);

/**
 *  @brief Cancel Asynchronous I/O Operation
 * 
 *  6.7.7 Cancel Asynchronous I/O Operation, P1003.1b-1993, p. 163
 * 
 *  @param[in] filedes is the file descriptor
 *  @param[in] aiocbp is the asynchronous I/O control block
 * 
 *  @return This method returns AIO_CANCELED if the requested operation(s)
 *          were canceled. Otherwise, AIO_NOTCANCELED is returned indicating
 *          that at least one of the requested operation(s) cannot be canceled
 */
int aio_cancel(
  int            filedes,
  struct aiocb  *aiocbp
);

/*
 *  6.7.7 Wait for Asynchronous I/O Request, P1003.1b-1993, p. 164
 */

int aio_suspend(
  const struct aiocb  * const   list[],
  int                     nent,
  const struct timespec  *timeout
);

#if defined(_POSIX_SYNCHRONIZED_IO)

/*
 *  6.7.9 Asynchronous File Synchronization, P1003.1b-1993, p. 166
 */

int aio_fsync(
  int            op,
  struct aiocb  *aiocbp
);

#endif /* _POSIX_SYNCHRONIZED_IO */

#endif /* _POSIX_ASYNCHRONOUS_IO */

#ifdef __cplusplus
}
#endif

#endif
/* end of include file */