CURLOPT_PROGRESSFUNCTION(3)

CURLOPT_PROGRESSFUNCTION(3curl_easy_setopt optionCURLOPT_PROGRESSFUNCTION(3)

NAME

     CURLOPT_PROGRESSFUNCTION - callback to progress meter  func-
     tion

SYNOPSIS

     #include <curl/curl.h>

     int progress_callback(void *clientp,
                           double dltotal,
                           double dlnow,
                           double ultotal,
                           double ulnow);

     CURLcode           curl_easy_setopt(CURL            *handle,
     CURLOPT_PROGRESSFUNCTION, progress_callback);

DESCRIPTION

     Pass a pointer to your callback function, which should match
     the prototype shown above.

     We     encourage     users     to     use     the      newer
     CURLOPT_XFERINFOFUNCTION(3) instead, if you can.

     This function gets called by libcurl instead of its internal
     equivalent  with  a  frequent  interval. While data is being
     transferred it will be called very  frequently,  and  during
     slow  periods  like when nothing is being transferred it can
     slow down to about one call per second.

     clientp is the pointer set with CURLOPT_PROGRESSDATA(3),  it
     is  not  used  by  libcurl but is only passed along from the
     application to the callback.

     The callback gets told how much data libcurl  will  transfer
     and  has  transferred,  in  number  of bytes. dltotal is the
     total number of bytes libcurl expects to  download  in  this
     transfer.  dlnow  is  the number of bytes downloaded so far.
     ultotal is the total number  of  bytes  libcurl  expects  to
     upload  in  this  transfer.  ulnow  is  the  number of bytes
     uploaded so far.

     Unknown/unused argument values passed to the  callback  will
     be  set  to zero (like if you only download data, the upload
     size will remain 0). Many times the callback will be  called
     one or more times first, before it knows the data sizes so a
     program must be made to handle that.

     Returning a non-zero value from  this  callback  will  cause
     libcurl     to     abort    the    transfer    and    return
     CURLE_ABORTED_BY_CALLBACK.

     If you transfer data with the multi interface, this function

libcurl 7.58.0   Last change: February 03, 2016                 1

CURLOPT_PROGRESSFUNCTION(3curl_easy_setopt optionCURLOPT_PROGRESSFUNCTION(3)

     will  not  be  called  during periods of idleness unless you
     call  the  appropriate  libcurl   function   that   performs
     transfers.

     CURLOPT_NOPROGRESS(3) must be set to 0 to make this function
     actually get called.

DEFAULT

     By default, libcurl has an internal progress  meter.  That's
     rarely wanted by users.

PROTOCOLS

     All

EXAMPLE

     https://curl.haxx.se/libcurl/c/progressfunc.html

AVAILABILITY

     Always

RETURN VALUE

     Returns CURLE_OK.

SEE ALSO

     CURLOPT_VERBOSE(3), CURLOPT_NOPROGRESS(3),

libcurl 7.58.0   Last change: February 03, 2016                 2