CURLMOPT\_PUSHDATA(3) Library Functions Manual CURLMOPT\_PUSHDATA(3)

# [NAME](#NAME)

CURLMOPT\_PUSHDATA - pointer to pass to push callback

# [SYNOPSIS](#SYNOPSIS)

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

# [DESCRIPTION](#DESCRIPTION)

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

# [DEFAULT](#DEFAULT)

NULL

# [PROTOCOLS](#PROTOCOLS)

This functionality affects http only

# [EXAMPLE](#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](#AVAILABILITY)

Added in curl 7.44.0

# [RETURN VALUE](#RETURN_VALUE)

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

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

# [SEE ALSO](#SEE_ALSO)

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

2026-10-19 libcurl

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Document: CURLMOPT_PUSHDATA(3) from curl 8.23.0-r1 (Chainguard OS)
Source: https://github.com/curl/curl.git