curl_multi_perform(3)

curl_multi_perform(3)    libcurl Manual     curl_multi_perform(3)

NAME

     curl_multi_perform - reads/writes available data  from  each
     easy handle

SYNOPSIS

     #include <curl/curl.h>

     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.

RETURN VALUE

     CURLMcode type, general libcurl multi interface error code.

     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".

     NOTE that this only returns errors etc regarding  the  whole
     multi  stack.  There  might  still have occurred problems on
     individual transfers even when this function returns OK.

TYPICAL USAGE

     Most application will use  curl_multi_fdset(3)  to  get  the
     multi_handle's  file descriptors, then it'll wait for action
     on them using select() 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 7.9.5       Last change: 1 March 2002                   1