CURLOPT_IOCTLDATA

Section: curl_easy_setopt options (3)
Updated: November 04, 2020
Page Index

NAME

CURLOPT_IOCTLDATA - custom pointer passed to I/O callback

SYNOPSIS

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 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.