curl_multi_select()

curl_multi_select() — Wait until reading or writing is possible for any cURL multi handle connection.

curl_multi_select() — Blocks the execution of the script until a cURL handle attached to the cURL multi handle would be able to make progress on the next call to curl_multi_exec or until the timeout strikes (whichever comes first).

Inputs: timeout: Time, in seconds, to wait for a response from the active cURL multi handle connections.

Returns: On success, returns the number of active descriptors contained in the descriptor sets. This may be 0 if there was no activity on any of the descriptors. On failure, this function will return -1 on a select failure (from the underlying select() system call).