CURLOPT_CHUNK_BGN_FUNCTION(3)

CURLOPT_CHUNK_BGN_FUNCTION(3curl_easy_setopt optionCURLOPT_CHUNK_BGN_FUNCTION(3)

NAME

     CURLOPT_CHUNK_BGN_FUNCTION - callback before a transfer with
     FTP wildcardmatch

SYNOPSIS

     #include <curl/curl.h>

     long chunk_bgn_callback(const void *transfer_info, void *ptr,
                             int remains);

     CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CHUNK_BGN_FUNCTION,
                               chunk_bgn_callback);

DESCRIPTION

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

     This callback function gets called by libcurl before a  part
     of  the  stream  is going to be transferred (if the transfer
     supports chunks).

     The  transfer_info  pointer   will   point   to   a   struct
     curl_fileinfo  with  details about the file that is about to
     get transferred.

     This   callback   makes   sense   only   when   using    the
     CURLOPT_WILDCARDMATCH(3) option for now.

     The  target  of  transfer_info  parameter  is   a   "feature
     depended" structure. For the FTP wildcard download, the tar-
     get  is  curl_fileinfo  structure  (see  curl/curl.h).   The
     parameter  ptr  is a pointer given by CURLOPT_CHUNK_DATA(3).
     The parameter remains contains number  of  chunks  remaining
     per  the  transfer.  If  the  feature  is not available, the
     parameter has zero value.

     Return  CURL_CHUNK_BGN_FUNC_OK  if   everything   is   fine,
     CURL_CHUNK_BGN_FUNC_SKIP  if  you  want to skip the concrete
     chunk or CURL_CHUNK_BGN_FUNC_FAIL to tell libcurl to stop if
     some error occurred.

DEFAULT

     NULL

PROTOCOLS

     FTP

EXAMPLE

     static long file_is_coming(struct curl_fileinfo *finfo,
                                struct callback_data *data,
                                int remains)
     {

libcurl 7.58.0      Last change: May 31, 2017                   1

CURLOPT_CHUNK_BGN_FUNCTION(3curl_easy_setopt optionCURLOPT_CHUNK_BGN_FUNCTION(3)

       printf("%3d %40s %10luB ", remains, finfo->filename,
              (unsigned long)finfo->size);

       switch(finfo->filetype) {
       case CURLFILETYPE_DIRECTORY:
         printf(" DIR0);
         break;
       case CURLFILETYPE_FILE:
         printf("FILE ");
         break;
       default:
         printf("OTHER0);
         break;
       }

       if(finfo->filetype == CURLFILETYPE_FILE) {
         /* do not transfer files >= 50B */
         if(finfo->size > 50) {
           printf("SKIPPED0);
           return CURL_CHUNK_BGN_FUNC_SKIP;
         }

         data->output = fopen(finfo->filename, "wb");
         if(!data->output) {
           return CURL_CHUNK_BGN_FUNC_FAIL;
         }
       }

       return CURL_CHUNK_BGN_FUNC_OK;
     }

     int main()
     {
       /* data for callback */
       struct callback_data callback_info;

       /* callback is called before download of concrete file started */
       curl_easy_setopt(curl, CURLOPT_CHUNK_BGN_FUNCTION, file_is_coming);
       curl_easy_setopt(curl, CURLOPT_CHUNK_DATA, &callback_info);
     }

AVAILABILITY

     This was added in 7.21.0

RETURN VALUE

     Returns  CURLE_OK  if   the   option   is   supported,   and
     CURLE_UNKNOWN_OPTION if not.

SEE ALSO

     CURLOPT_CHUNK_END_FUNCTION(3), CURLOPT_WILDCARDMATCH(3),

libcurl 7.58.0      Last change: May 31, 2017                   2