docs/libcurl/opts/CURLOPT_SOCKOPTDATA.3

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.TH CURLOPT_SOCKOPTDATA 3 "May 15, 2017" "libcurl 7.61.1" "curl_easy_setopt options"

.SH NAME
CURLOPT_SOCKOPTDATA \- custom pointer to pass to sockopt callback
.SH SYNOPSIS
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SOCKOPTDATA, void *pointer);
.SH DESCRIPTION
Pass a \fIpointer\fP that will be untouched by libcurl and passed as the first
argument in the sockopt callback set with \fICURLOPT_SOCKOPTFUNCTION(3)\fP.
.SH DEFAULT
The default value of this parameter is NULL.
.SH PROTOCOLS
All
.SH EXAMPLE
.nf
static int sockopt_callback(void *clientp, curl_socket_t curlfd,
                            curlsocktype purpose)
{
  int val = *(int *)clientp;
  setsockopt(curldfd, SOL_SOCKET, SO_RCVBUF, (const char *)&val, sizeof(val));
  return CURL_SOCKOPT_OK;
}

curl = curl_easy_init();
if(curl) {
  int recvbuffersize = 256 * 1024;

  curl_easy_setopt(curl, CURLOPT_URL, "http://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 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_SOCKOPTFUNCTION "(3), " CURLOPT_OPENSOCKETFUNCTION "(3), "