.\" generated by cd2nroff 0.1 from CURLOPT_SOCKOPTDATA.md
.TH CURLOPT_SOCKOPTDATA 3 "2024-11-18" libcurl
.SH NAME
CURLOPT_SOCKOPTDATA \- pointer to pass to sockopt callback
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SOCKOPTDATA, void *pointer);
.fi
.SH DESCRIPTION
Pass a \fIpointer\fP that is untouched by libcurl and passed as the first
argument in the sockopt callback set with \fICURLOPT_SOCKOPTFUNCTION(3)\fP.
.SH DEFAULT
NULL
.SH PROTOCOLS
This functionality affects all supported protocols
.SH EXAMPLE
.nf
static int sockopt_callback(void *clientp, curl_socket_t curlfd,
                            curlsocktype purpose)
{
  int val = *(int *)clientp;
  setsockopt((int)curlfd, SOL_SOCKET, SO_RCVBUF,
             (const char *)&val, sizeof(val));
  return CURL_SOCKOPT_OK;
}

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    int recvbuffersize = 256 * 1024;

    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");

    /* call this function to set options for the socket */
    curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
    curl_easy_setopt(curl, CURLOPT_SOCKOPTDATA, &recvbuffersize);

    res = curl_easy_perform(curl);

    curl_easy_cleanup(curl);
  }
}
.fi
.SH AVAILABILITY
Added in curl 7.16.0
.SH RETURN VALUE
Returns \fICURLE_OK\fP if the option is supported, and \fICURLE_UNKNOWN_OPTION\fP if not.
.SH SEE ALSO
.BR CURLOPT_OPENSOCKETFUNCTION (3),
.BR CURLOPT_SOCKOPTFUNCTION (3)