Manpages - CURLOPT_IOCTLDATA.3

CURLOPT_IOCTLDATA - pointer passed to I/O callback

#include <curl/curl.h>

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

Pass the pointer that will be untouched by libcurl and passed as the 3rd argument in the ioctl callback set with CURLOPT_IOCTLFUNCTION(3).

By default, the value of this parameter is NULL.

Used with HTTP

  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);
  }

Added in 7.12.3

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

*CURLOPT_IOCTLFUNCTION*(3), *CURLOPT_SEEKFUNCTION*(3),