CURLOPT_SEEKDATA(3) - Man pages

CURLOPT_SEEKDATA(3)         Library Functions Manual        CURLOPT_SEEKDATA(3)

NAME
       CURLOPT_SEEKDATA - pointer passed to the seek callback

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SEEKDATA, void *pointer);

DESCRIPTION
       Data  pointer to pass to the seek callback function. If you use the CUR-
       LOPT_SEEKFUNCTION(3) option, this is the pointer you get as input.

DEFAULT
       If you do not set this, NULL is passed to the callback.

PROTOCOLS
       This functionality affects ftp, http and sftp

EXAMPLE
       #include <unistd.h> /* for lseek() */

       struct data {
         int our_fd;
       };

       static int seek_cb(void *clientp, curl_off_t offset, int origin)
       {
         struct data *d = (struct data *)clientp;
         lseek(d->our_fd, offset, origin);
         return CURL_SEEKFUNC_OK;
       }

       int main(void)
       {
         struct data seek_data;
         CURL *curl = curl_easy_init();
         if(curl) {
           curl_easy_setopt(curl, CURLOPT_SEEKFUNCTION, seek_cb);
           curl_easy_setopt(curl, CURLOPT_SEEKDATA, &seek_data);
         }
       }

AVAILABILITY
       Added in curl 7.18.0

RETURN VALUE
SEE ALSO
       CURLOPT_DEBUGFUNCTION(3),  CURLOPT_IOCTLFUNCTION(3),   CURLOPT_SEEKFUNC-
       TION(3), CURLOPT_STDERR(3)

libcurl                            2026-07-12               CURLOPT_SEEKDATA(3)

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