aio_write(3) — Linux manual page

aio_write(3)            Library Functions Manual            aio_write(3)

NAME

       aio_write - asynchronous write

LIBRARY

       Real-time library (librt, -lrt)

SYNOPSIS

       #include <aio.h>

       int aio_write(struct aiocb *aiocbp);

DESCRIPTION

       The aio_write() function queues the I/O request described by the
       buffer pointed to by aiocbp.  This function is the asynchronous
       analog of write(2).  The arguments of the call

           write(fd, buf, count)

       correspond (in order) to the fields aio_fildes, aio_buf, and
       aio_nbytes of the structure pointed to by aiocbp.  (See aio(7)
       for a description of the aiocb structure.)

       If O_APPEND is not set, the data is written starting at the
       absolute position aiocbp->aio_offset, regardless of the file
       offset.  If O_APPEND is set, data is written at the end of the
       file in the same order as aio_write() calls are made.  After the
       call, the value of the file offset is unspecified.

       The "asynchronous" means that this call returns as soon as the
       request has been enqueued; the write may or may not have
       completed when the call returns.  One tests for completion using
       aio_error(3).  The return status of a completed I/O operation can
       be obtained aio_return(3).  Asynchronous notification of I/O
       completion can be obtained by setting aiocbp->aio_sigevent
       appropriately; see sigevent(3type) for details.

       If _POSIX_PRIORITIZED_IO is defined, and this file supports it,
       then the asynchronous operation is submitted at a priority equal
       to that of the calling process minus aiocbp->aio_reqprio.

       The field aiocbp->aio_lio_opcode is ignored.

       No data is written to a regular file beyond its maximum offset.

RETURN VALUE

       On success, 0 is returned.  On error, the request is not
       enqueued, -1 is returned, and errno is set to indicate the error.
       If an error is detected only later, it will be reported via
       aio_return(3) (returns status -1) and aio_error(3) (error status—
       whatever one would have gotten in errno, such as EBADF).

ERRORS

       EAGAIN Out of resources.

       EBADF  aio_fildes is not a valid file descriptor open for
              writing.

       EFBIG  The file is a regular file, we want to write at least one
              byte, but the starting position is at or beyond the
              maximum offset for this file.

       EINVAL One or more of aio_offset, aio_reqprio, aio_nbytes are
              invalid.

       ENOSYS aio_write() is not implemented.

ATTRIBUTES

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌─────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                           │ Attribute     │ Value   │
       ├─────────────────────────────────────┼───────────────┼─────────┤
       │ aio_write()                         │ Thread safety │ MT-Safe │
       └─────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       POSIX.1-2008.

HISTORY

       glibc 2.1.  POSIX.1-2001.

NOTES

       It is a good idea to zero out the control block before use.  The
       control block must not be changed while the write operation is in
       progress.  The buffer area being written out must not be accessed
       during the operation or undefined results may occur.  The memory
       areas involved must remain valid.

       Simultaneous I/O operations specifying the same aiocb structure
       produce undefined results.

SEE ALSO

       aio_cancel(3), aio_error(3), aio_fsync(3), aio_read(3),
       aio_return(3), aio_suspend(3), lio_listio(3), aio(7)

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                   aio_write(3)

Pages that refer to this page: execve(2), fork(2), aio_cancel(3), aiocb(3type), aio_error(3), aio_fsync(3), aio_read(3), aio_return(3), aio_suspend(3), lio_listio(3), aio(7)

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