Manual Pages for UNIX Operating System command usage for man curl_multi_perform

libcurl Manual                              curl_multi_perform(3)



NAME
     curl_multi_perform - reads/writes available data  from  each
     easy handle

SYNOPSIS
     #include 

     CURLMcode   curl_multi_perform(CURLM   *multi_handle,    int
     *running_handles);

DESCRIPTION
     When  the  app  thinks  there's  data  available   for   the
     multi_handle,  it  should  call  this function to read/write
     whatever  there   is   to   read   or   write   right   now.
     curl_multi_perform() returns as soon as the reads/writes are
     done. This function does not require that there actually  is
     any  data available for reading or that data can be written,
     it can be called just in case. It will write the  number  of
     handles  that  still  transfer data in the second argument's
     integer-pointer.

     When  you  call  curl_multi_perform()  and  the  amount   of
     running_handles  is  changed  from  the previous call (or is
     less than the amount of easy handles  you've  added  to  the
     multi  handle), you know that there is one or more transfers
     less "running". You can then call curl_multi_info_read(3) to
     get  information  about  each individual completed transfer,
     and that returned info includes CURLcode  and  more.  If  an
     added  handle fails very quickly, it may never be counted as
     a running_handle.

     When running_handles is set to zero (0)  on  the  return  of
     this function, there is no longer any transfers in progress.

RETURN VALUE
     CURLMcode type, general libcurl multi interface error code.

     Before     version     7.20.0:      If      you      receive
     CURLM_CALL_MULTI_PERFORM,  this  basically  means  that  you
     should call curl_multi_perform again, before you select() on
     more  actions.  You don't have to do it immediately, but the
     return code means that libcurl may have more data  available
     to  return or that there may be more data to send off before
     it is "satisfied". Do note that  curl_multi_perform(3)  will
     return  CURLM_CALL_MULTI_PERFORM  only  when  it wants to be
     called again immediately. When things are fine and there  is
     nothing  immediate  it wants done, it'll return CURLM_OK and
     you need to wait for "action" and then  call  this  function
     again.

     This function only returns errors etc  regarding  the  whole
     multi   stack.    Problems  still  might  have  occurred  on



libcurl 7.9.5       Last change: 1 March 2002                   1






libcurl Manual                              curl_multi_perform(3)



     individual  transfers  even  when  this   function   returns
     CURLM_OK.

TYPICAL USAGE
     Most applications will use curl_multi_fdset(3)  to  get  the
     multi_handle's  file descriptors, then it'll wait for action
     on them using select(3) and as soon as one or more  of  them
     are ready, curl_multi_perform(3) gets called.

SEE ALSO
     curl_multi_cleanup(3),                   curl_multi_init(3),
     curl_multi_fdset(3),    curl_multi_info_read(3),    libcurl-
     errors(3)

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     _______________________________________
    |   ATTRIBUTE TYPE   |  ATTRIBUTE VALUE|
    |____________________|__________________|_
    | Availability       |  web/curl       |
    |____________________|__________________|_
    | Interface Stability|  Uncommitted    |
    |____________________|_________________|

NOTES
     Source for C-URL is available on http://opensolaris.org.



























libcurl 7.9.5       Last change: 1 March 2002                   2