.\" generated by cd2nroff 0.1 from CURLOPT_PREREQDATA.md
.TH CURLOPT_PREREQDATA 3 "2024-11-18" libcurl
.SH NAME
CURLOPT_PREREQDATA \- pointer passed to the pre\-request callback
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PREREQDATA, void *pointer);
.fi
.SH DESCRIPTION
Pass a \fIpointer\fP that is untouched by libcurl and passed as the first
argument in the pre\-request callback set with \fICURLOPT_PREREQFUNCTION(3)\fP.
.SH DEFAULT
NULL
.SH PROTOCOLS
This functionality affects all supported protocols
.SH EXAMPLE
.nf
struct priv {
  void *custom;
};

static int prereq_callback(void *clientp,
                           char *conn_primary_ip,
                           char *conn_local_ip,
                           int conn_primary_port,
                           int conn_local_port)
{
  printf("Connection made to %s:%d\\n", conn_primary_ip, conn_primary_port);
  return CURL_PREREQFUNC_OK;
}

int main(void)
{
  struct priv prereq_data;
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_PREREQFUNCTION, prereq_callback);
    curl_easy_setopt(curl, CURLOPT_PREREQDATA, &prereq_data);
    curl_easy_perform(curl);
  }
}
.fi
.SH AVAILABILITY
Added in curl 7.80.0
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH SEE ALSO
.BR CURLINFO_PRIMARY_IP (3),
.BR CURLINFO_PRIMARY_PORT (3),
.BR CURLOPT_PREREQFUNCTION (3)