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

# [NAME](#NAME)

CURLMOPT\_TIMERDATA - custom pointer to pass to timer callback

# [SYNOPSIS](#SYNOPSIS)

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

# [DESCRIPTION](#DESCRIPTION)

A data **pointer** to pass to the timer callback set with the [*CURLMOPT\_TIMERFUNCTION(3)*](/man/os/curl/CURLMOPT_TIMERFUNCTION.3) option.

This pointer is not touched by libcurl but is only be passed in to the timer callback's **clientp** argument.

# [DEFAULT](#DEFAULT)

NULL

# [PROTOCOLS](#PROTOCOLS)

This functionality affects all supported protocols

# [EXAMPLE](#EXAMPLE)

```
struct priv {


  void *custom;
};
static int timerfunc(CURLM *multi, long timeout_ms, void *clientp)
{


  struct priv *mydata = clientp;


  printf("our ptr: %p\n", mydata->custom);


  if(timeout_ms >= 0) {


    /* this is the new single timeout to wait for */


  }


  else {


    /* delete the timeout, nothing to wait for now */


  }


  return 0;
}
int main(void)
{


  struct priv mydata;


  CURLM *multi = curl_multi_init();


  curl_multi_setopt(multi, CURLMOPT_TIMERFUNCTION, timerfunc);


  curl_multi_setopt(multi, CURLMOPT_TIMERDATA, &mydata);
}
```

# [AVAILABILITY](#AVAILABILITY)

Added in curl 7.16.0

# [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\_SOCKETFUNCTION**(3)](/man/os/curl/CURLMOPT_SOCKETFUNCTION.3), [**CURLMOPT\_TIMERFUNCTION**(3)](/man/os/curl/CURLMOPT_TIMERFUNCTION.3)

2026-10-14 libcurl

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Document: CURLMOPT_TIMERDATA(3) from curl 8.23.0-r0 (Chainguard OS)
Source: https://github.com/curl/curl.git