curl\_multi\_timeout(3) Library Functions Manual curl\_multi\_timeout(3)

# [NAME](#NAME)

curl\_multi\_timeout - how long to wait for action before proceeding

# [SYNOPSIS](#SYNOPSIS)

```
#include <curl/curl.h>
CURLMcode curl_multi_timeout(CURLM *multi_handle, long *timeout);
```

# [DESCRIPTION](#DESCRIPTION)

An application using the libcurl multi interface should call [*curl\_multi\_timeout(3)*](/man/os/curl/curl_multi_timeout.3) to figure out how long it should wait for socket actions - at most - before proceeding.

Proceeding means either doing the socket-style timeout action: call the [*curl\_multi\_socket\_action(3)*](/man/os/curl/curl_multi_socket_action.3) function with the **sockfd** argument set to CURL\_SOCKET\_TIMEOUT, or call [*curl\_multi\_perform(3)*](/man/os/curl/curl_multi_perform.3) if you are using the simpler and older multi interface approach.

The timeout value returned in the long **timeout\_ms** points to, is in number of milliseconds at this moment. If 0, it means you should proceed immediately without waiting for anything. If it returns -1, there is no timeout at all set.

An application that uses the *multi\_socket* API should not use this function. It should instead use the [*CURLMOPT\_TIMERFUNCTION(3)*](/man/os/curl/CURLMOPT_TIMERFUNCTION.3) option for proper and desired behavior.

Note: if libcurl returns a -1 timeout here, it means that libcurl currently has no stored timeout value. You must not wait too long (more than a few seconds perhaps) before you call [*curl\_multi\_perform(3)*](/man/os/curl/curl_multi_perform.3) again.

# [PROTOCOLS](#PROTOCOLS)

This functionality affects all supported protocols

# [EXAMPLE](#EXAMPLE)

```
int main(void)
{


  struct timeval timeout;


  long timeo;


  fd_set fdread;


  fd_set fdwrite;


  fd_set fdexcep;


  int maxfd = 2;


  CURLM *multi = curl_multi_init();


  curl_multi_timeout(multi, &timeo);


  if(timeo < 0)


    /* no set timeout, use a default */


    timeo = 980;


  timeout.tv_sec = timeo / 1000;


  timeout.tv_usec = (timeo % 1000) * 1000;


  /* wait for activities no longer than the set timeout */


  select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
}
```

# [TYPICAL USAGE](#TYPICAL_USAGE)

Call [*curl\_multi\_timeout(3)*](/man/os/curl/curl_multi_timeout.3), then wait for action on the sockets. Figure out which sockets to wait for by calling [*curl\_multi\_fdset(3)*](/man/os/curl/curl_multi_fdset.3).

When there is activity or timeout, call [*curl\_multi\_perform(3)*](/man/os/curl/curl_multi_perform.3) and then loop - until all transfers are complete.

# [AVAILABILITY](#AVAILABILITY)

Added in curl 7.15.4

# [RETURN VALUE](#RETURN_VALUE)

This function 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)

[**curl\_multi\_fdset**(3)](/man/os/curl/curl_multi_fdset.3), [**curl\_multi\_info\_read**(3)](/man/os/curl/curl_multi_info_read.3), [**curl\_multi\_setopt**(3)](/man/os/curl/curl_multi_setopt.3), [**curl\_multi\_socket**(3)](/man/os/curl/curl_multi_socket.3)

2026-10-31 libcurl

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Document: curl_multi_timeout(3) from curl 8.23.0-r3 (Chainguard OS)
Source: https://github.com/curl/curl.git