---
name: "CURLMOPT_PUSHDATA"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLMOPT_PUSHDATA"
---

# CURLMOPT\_PUSHDATA(3)

pointer to pass to push callback

## NAME

CURLMOPT\_PUSHDATA - pointer to pass to push callback

## SYNOPSIS

```
#include <curl/curl.h>
CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_PUSHDATA, void *pointer);
```

## DESCRIPTION

Set a *pointer* to pass as the last argument to the *[CURLMOPT\_PUSHFUNCTION(3)](/CURLMOPT_PUSHFUNCTION/3.md)* callback. The pointer is not touched or used by libcurl itself, only passed on to the callback function.

## DEFAULT

NULL

## PROTOCOLS

This functionality affects http only

## EXAMPLE

```
#include <string.h>
/* only allow pushes for filenames starting with "push-" */
static 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);
}
```

## AVAILABILITY

Added in curl 7.44.0

## RETURN VALUE

*[curl\_multi\_setopt(3)](/curl_multi_setopt/3.md)* returns a CURLMcode indicating success or error.

CURLM\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLMOPT\_PIPELINING**(3)](/CURLMOPT_PIPELINING/3.md), [**CURLMOPT\_PUSHFUNCTION**(3)](/CURLMOPT_PUSHFUNCTION/3.md), [**CURLOPT\_PIPEWAIT**(3)](/CURLOPT_PIPEWAIT/3.md), **RFC**7540