NAME

aio.h - asynchronous input and output (REALTIME)

SYNOPSIS

^[AIO] #include <aio.h>

DESCRIPTION

The <aio.h> header shall define the aiocb structure which shall include at least the following members:

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. 

This header shall also include the following constants:

AIO_ALLDONE

A return value indicating that none of the requested operations could be canceled since they are already complete.

AIO_CANCELED

A return value indicating that all requested operations have been canceled.

AIO_NOTCANCELED

A return value indicating that some of the requested operations could not be canceled since they are in progress.

LIO_NOP

A lio_listio() element operation option indicating that no transfer is requested.

LIO_NOWAIT

A lio_listio() synchronization operation indicating that the calling thread is to continue execution while the lio_listio() operation is being performed, and no notification is given when the operation is complete.

LIO_READ

A lio_listio() element operation option requesting a read.

LIO_WAIT

A lio_listio() synchronization operation indicating that the calling thread is to suspend until the lio_listio() operation is complete.

LIO_WRITE

A lio_listio() element operation option requesting a write.

The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.

int      aio_cancel(int, struct aiocb *);
int      aio_error(const struct aiocb *);
int      aio_fsync(int, struct aiocb *);
int      aio_read(struct aiocb *);
ssize_t  aio_return(struct aiocb *);
int      aio_suspend(const struct aiocb *const[], int,
             const struct timespec *);
int      aio_write(struct aiocb *);
int      lio_listio(int, struct aiocb *restrict const[restrict], int,
             struct sigevent *restrict);

Inclusion of the <aio.h> header may make visible symbols defined in the headers <fcntl.h>, <signal.h>, <sys/types.h>, and <time.h>.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

<fcntl.h> , <signal.h> , <sys/types.h> , <time.h> , the System Interfaces volume of IEEE Std 1003.1-2001, fsync(), lseek(), read(), write()

CHANGE HISTORY

First released in Issue 5. Included for alignment with the POSIX Realtime Extension.

Issue 6

The <aio.h> header is marked as part of the Asynchronous Input and Output option.

The description of the constants is expanded.

The restrict keyword is added to the prototype for lio_listio().