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Problem with aio_write() function
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aio_read(3) Library Functions Manual aio_read(3) NAME
aio_read - Queues a single asynchronous read request LIBRARY
Asynchronous I/O Library (libaio, libaio_raw) SYNOPSIS
#include <aio.h> int aio_read ( struct aiocb *aiocbp ); PARAMETERS
*aiocbp A pointer to an aiocb structure. DESCRIPTION
The aio_read function allows the calling process to asynchronously read aiocbp->aio_nbytes from the file associated with aiocbp->aio_fildes into the buffer pointed to by aiocbp->aio_buf. The aio_read function issues a read request and returns even when the data cannot be delivered immediately. If the request cannot be initi- ated, the aio_read function returns with an error status. If an error condition occurs during queuing, the function call returns without initiating the queue request. The aiocbp value may be used as an argument to the aio_error and aio_return functions to determine the error or return status of the asynchronous read operation. The requested operation takes place at the absolute position in the file as given by aio_offset, as if lseek() were called immediately prior to the operation with an offset equal to aio_offset and a whence equal to SEEK_SET. The aiocbp argument points to an asynchronous control block structure, aiocb, used in the asynchronous I/O interfaces. The aiocb structure contains asynchronous operation information, such as the file offset for the read operation. The aiocb structure has the following mem- bers: int aio_fildes; off_t aio_offset; volatile void *aio_buf; size_t aio_nbytes; int aio_reqprio; struct sigevent aio_sigevent; int aio_lio_opcode; The aio_fildes member is the file descriptor on which the asynchronous operation is to be performed. After any asynchronous I/O operation, the aio_offset member is undefined and must be set explicitly for every asynchronous I/O request. The aio_nbytes and aio_buf members are the same as the nbyte and buf arguments defined by POSIX.1 read and write functions. The aio_sigevent member of the aiocb structure defines the signal generated when the I/O operation is complete. If aio_sigevent.sigev_notify equals SIGEV_SIGNAL and aio_sigevent.sigev_signo is non-zero, a signal is generated when the asynchronous read operation has completed. The aio_lio_opcode and aio_reqprio members are ignored by aio_read(). Pending asynchronous I/O operations are handled as follows: o On close, _exit, or exec, any I/O that was directed to a file system file, a tty device, or a streams device is canceled. Any I/O that was directed to any raw character device, excluding terminal and streams devices, is not canceled. o On fork, no asynchronous I/O is inherited. RETURN VALUES
On an unsuccessful call, a value of -1 is returned and errno is set to indicate the type of error that occurred. ERRORS
The aio_read function fails under the following conditions: [EAGAIN] The requested asynchronous I/O operation was not queued due to system resource limitations. [EBADF] The aiocbp->aio_fildes argument is not a valid file descriptor open for reading. [EINVAL] The file offset value implied by aiocbp->aio_offset would be invalid. On a successful call, a value of 0 (zero) is returned and the I/O operation is queued. After successful queuing of aio_read, return and error values are the same as for a call to the read function. One of the following additional errors may occur: [ECANCELED] The operation was canceled by aio_cancel. [EINVAL] The offset in aio_offset is invalid for the file specified. RELATED INFORMATION
Functions: close(2), exec(2), _exit(2), fork(2), lseek(2), read(2), write(2), aio_cancel(3), aio_error(3), aio_group_completion_np(3), aio_results_np(3), aio_return(3), aio_suspend(3), aio_write(3), lio_listio(3) Guide to Realtime Programming delim off aio_read(3)
Problem with aio_write() function