repo/core/curl/files/CURLMOPT_PUSHDATA.3

.\" generated by cd2nroff 0.1 from CURLMOPT_PUSHDATA.md
.TH CURLMOPT_PUSHDATA 3 "2024-08-02" libcurl
.SH NAME
CURLMOPT_PUSHDATA \- pointer to pass to push callback
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_PUSHDATA, void *pointer);
.fi
.SH DESCRIPTION
Set a \fIpointer\fP to pass as the last argument to the
\fICURLMOPT_PUSHFUNCTION(3)\fP callback. The pointer is not touched or used by
libcurl itself, only passed on to the callback function.
.SH DEFAULT
NULL
.SH PROTOCOLS
This functionality affects http only
.SH EXAMPLE
.nf
#include <string.h>

/* only allow pushes for filenames starting with "push-" */
int push_callback(CURL *parent,
                  CURL *easy,
                  size_t num_headers,
                  struct curl_pushheaders *headers,
                  void *clientp)
{
  char *headp;
  int *transfers = (int *)clientp;
  FILE *out;
  headp = curl_pushheader_byname(headers, ":path");
  if(headp && !strncmp(headp, "/push-", 6)) {
    fprintf(stderr, "The PATH is %s\\n", headp);

    /* save the push here */
    out = fopen("pushed-stream", "wb");

    /* write to this file */
    curl_easy_setopt(easy, CURLOPT_WRITEDATA, out);

    (*transfers)++; /* one more */

    return CURL_PUSH_OK;
  }
  return CURL_PUSH_DENY;
}

int main(void)
{
  int counter;
  CURLM *multi = curl_multi_init();
  curl_multi_setopt(multi, CURLMOPT_PUSHFUNCTION, push_callback);
  curl_multi_setopt(multi, CURLMOPT_PUSHDATA, &counter);
}
.fi
.SH AVAILABILITY
Added in curl 7.44.0
.SH RETURN VALUE
Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION if not.
.SH SEE ALSO
.BR CURLMOPT_PIPELINING (3),
.BR CURLMOPT_PUSHFUNCTION (3),
.BR CURLOPT_PIPEWAIT (3),
.BR RFC 7540