| 1 | .TH aio_suspend 3 2002-09-12 "Linux 2.4" Linux AIO" |
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| 2 | .SH NAME |
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| 3 | aio_suspend \- Wait until one or more requests of a specific set terminates. |
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| 4 | .SH SYNOPSYS |
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| 5 | .nf |
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| 6 | .B "#include <errno.h>" |
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| 7 | .sp |
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| 8 | .br |
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| 9 | .B "#include <aio.h>" |
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| 10 | .sp |
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| 11 | .br |
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| 12 | .BI "int aio_suspend (const struct aiocb *const list[], int nent, const struct timespec *timeout)" |
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| 13 | .fi |
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| 14 | .SH DESCRIPTION |
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| 15 | Another method of synchronization is to wait until one or more requests of a |
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| 16 | specific set terminated. This could be achieved by the |
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| 17 | .IR "aio_*" |
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| 18 | functions to notify the initiating process about the termination but in |
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| 19 | some situations this is not the ideal solution. In a program which |
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| 20 | constantly updates clients somehow connected to the server it is not |
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| 21 | always the best solution to go round robin since some connections might |
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| 22 | be slow. On the other hand letting the |
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| 23 | .IR "aio_*" |
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| 24 | function notify the |
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| 25 | caller might also be not the best solution since whenever the process |
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| 26 | works on preparing data for on client it makes no sense to be |
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| 27 | interrupted by a notification since the new client will not be handled |
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| 28 | before the current client is served. For situations like this |
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| 29 | .IR "aio_suspend" |
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| 30 | should be used. |
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| 31 | .PP |
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| 32 | When calling this function, the calling thread is suspended until at |
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| 33 | least one of the requests pointed to by the |
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| 34 | .IR "nent" |
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| 35 | elements of the |
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| 36 | array |
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| 37 | .IR "list" |
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| 38 | has completed. If any of the requests has already |
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| 39 | completed at the time |
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| 40 | .IR "aio_suspend" |
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| 41 | is called, the function returns |
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| 42 | immediately. Whether a request has terminated or not is determined by |
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| 43 | comparing the error status of the request with |
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| 44 | .IR "EINPROGRESS" |
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| 45 | . If |
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| 46 | an element of |
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| 47 | .IR "list" |
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| 48 | is |
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| 49 | .IR "NULL" |
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| 50 | , the entry is simply ignored. |
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| 51 | |
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| 52 | If no request has finished, the calling process is suspended. If |
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| 53 | .IR "timeout" |
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| 54 | is |
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| 55 | .IR "NULL" |
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| 56 | , the process is not woken until a request |
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| 57 | has finished. If |
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| 58 | .IR "timeout" |
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| 59 | is not |
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| 60 | .IR "NULL" |
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| 61 | , the process remains |
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| 62 | suspended at least as long as specified in |
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| 63 | .IR "timeout" |
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| 64 | . In this case, |
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| 65 | .IR "aio_suspend" |
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| 66 | returns with an error. |
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| 67 | .PP |
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| 68 | When the sources are compiled with |
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| 69 | .IR "_FILE_OFFSET_BITS == 64" |
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| 70 | this |
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| 71 | function is in fact |
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| 72 | .IR "aio_suspend64" |
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| 73 | since the LFS interface |
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| 74 | transparently replaces the normal implementation. |
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| 75 | .SH "RETURN VALUES" |
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| 76 | The return value of the function is |
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| 77 | .IR 0 |
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| 78 | if one or more requests |
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| 79 | from the |
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| 80 | .IR "list" |
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| 81 | have terminated. Otherwise the function returns |
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| 82 | .IR -1 |
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| 83 | and |
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| 84 | .IR "errno" |
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| 85 | is set. |
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| 86 | .SH ERRORS |
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| 87 | .TP |
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| 88 | .B EAGAIN |
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| 89 | None of the requests from the |
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| 90 | .IR "list" |
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| 91 | completed in the time specified |
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| 92 | by |
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| 93 | .IR "timeout" |
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| 94 | . |
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| 95 | .TP |
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| 96 | .B EINTR |
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| 97 | A signal interrupted the |
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| 98 | .IR "aio_suspend" |
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| 99 | function. This signal might |
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| 100 | also be sent by the AIO implementation while signalling the termination |
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| 101 | of one of the requests. |
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| 102 | .TP |
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| 103 | .B ENOSYS |
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| 104 | The |
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| 105 | .IR "aio_suspend" |
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| 106 | function is not implemented. |
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| 107 | .SH "SEE ALSO" |
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| 108 | .BR aio(3), |
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| 109 | .BR aio_cancel(3), |
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| 110 | .BR aio_cancel64(3), |
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| 111 | .BR aio_error(3), |
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| 112 | .BR aio_error64(3), |
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| 113 | .BR aio_fsync(3), |
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| 114 | .BR aio_fsync64(3), |
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| 115 | .BR aio_init(3), |
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| 116 | .BR aio_read(3), |
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| 117 | .BR aio_read64(3), |
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| 118 | .BR aio_return(3), |
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| 119 | .BR aio_return64(3), |
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| 120 | .BR aio_suspend64(3), |
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| 121 | .BR aio_write(3), |
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| 122 | .BR aio_write64(3), |
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| 123 | .BR errno(3), |
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