aio_suspend — wait for asynchronous I/O operation or timeout


#include <aio.h>
int aio_suspend( const struct aiocb * const aiocb_list[],
  int nitems,
  const struct timespec *timeout);
[Note] Note

Link with −lrt.


The aio_suspend() function suspends the calling thread until one of the following occurs:

  • One or more of the asynchronous I/O requests in the list aiocb_list has completed.

  • A signal is delivered.

  • timeout is not NULL and the specified time interval has passed. (For details of the timespec structure, see nanosleep(2).)

The nitems argument specifies the number of items in aiocb_list. Each item in the list pointed to by aiocb_list must be either NULL (and then is ignored), or a pointer to a control block on which I/O was initiated using aio_read(3), aio_write(3), or lio_listio(3). (See aio(7) for a description of the aiocb structure.)

If CLOCK_MONOTONIC is supported, this clock is used to measure the timeout interval (see clock_gettime(3)).


If this function returns after completion of one of the I/O requests specified in aiocb_list, 0 is returned. Otherwise, −1 is returned, and errno is set to indicate the error.



The call timed out before any of the indicated operations had completed.


The call was ended by signal (possibly the completion signal of one of the operations we were waiting for); see signal(7).


aio_suspend() is not implemented.


The aio_suspend() function is available since glibc 2.1.


For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
aio_suspend() Thread safety MT-Safe


POSIX.1-2001, POSIX.1-2008.


One can achieve polling by using a non-NULL timeout that specifies a zero time interval.

If one or more of the asynchronous I/O operations specified in aiocb_list has already completed at the time of the call to aio_suspend(), then the call returns immediately.

To determine which I/O operations have completed after a successful return from aio_suspend(), use aio_error(3) to scan the list of aiocb structures pointed to by aiocb_list.


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


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  Copyright (c) 2003 Andries Brouwer (
and Copyright (C) 2010 Michael Kerrisk <>

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