DOKK / manpages / debian 12 / libcurl4-doc / CURLOPT_IOCTLDATA.3.en
CURLOPT_IOCTLDATA(3) curl_easy_setopt options 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. Deprecated since 7.18.0.

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

CURLOPT_IOCTLFUNCTION(3), CURLOPT_SEEKFUNCTION(3),

January 2, 2023 libcurl 7.88.1