CURLOPT_IOCTLDATA(3)       curl_easy_setopt options       CURLOPT_IOCTLDATA(3)

NAME
       CURLOPT_IOCTLDATA - custom pointer passed to I/O callback

SYNOPSIS
       #include <curl/curl.h>

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

DESCRIPTION
       Pass the pointer that will be untouched by libcurl and passed as the
       3rd argument in the ioctl callback set with _IOCTLFUNCTION&section=3">CURLOPT_IOCTLFUNCTION(3).

DEFAULT
       By default, the value of this parameter is NULL.

PROTOCOLS
       Used with HTTP

EXAMPLE
       static curlioerr ioctl_callback(CURL *handle, int cmd, void *clientp)
       {
         struct data *io = (struct data *)clientp;
         if(cmd == CURLIOCMD_RESTARTREAD) {
           lseek(fd, 0, SEEK_SET);
           current_offset = 0;
           return CURLIOE_OK;
         }
         return CURLIOE_UNKNOWNCMD;
       }
       {
         struct data ioctl_data;
         curl_easy_setopt(curl, CURLOPT_IOCTLFUNCTION, ioctl_callback);
         curl_easy_setopt(curl, CURLOPT_IOCTLDATA, &ioctl_data);
       }

AVAILABILITY
       Added in 7.12.3

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

SEE ALSO
       CURLOPT_IOCTLFUNCTION(3), CURLOPT_SEEKFUNCTION(3),

libcurl 7.77.0                 November 4, 2020           CURLOPT_IOCTLDATA(3)