.\" generated by cd2nroff 0.1 from CURLOPT_TRAILERDATA.md
.TH CURLOPT_TRAILERDATA 3 "2025-07-07" libcurl
.SH NAME
CURLOPT_TRAILERDATA \- pointer passed to trailing headers callback
.SH SYNOPSIS
.nf
#include <curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TRAILERDATA, void *userdata);
.fi
.SH DESCRIPTION
Data pointer to be passed to the HTTP trailer callback function.
.SH DEFAULT
NULL
.SH PROTOCOLS
This functionality affects http only
.SH EXAMPLE
.nf
struct MyData {
  void *custom;
};

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    struct MyData data;
    curl_easy_setopt(curl, CURLOPT_TRAILERDATA, &data);
  }
}
.fi
.SH AVAILABILITY
Added in curl 7.64.0
.SH RETURN VALUE
\fIcurl_easy_setopt(3)\fP returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non\-zero means an error occurred, see
\fIlibcurl\-errors(3)\fP.
.SH SEE ALSO
.BR CURLOPT_TRAILERFUNCTION (3),
.BR CURLOPT_WRITEFUNCTION (3)