CURLOPT_TIMEOUT (3) - Linux Manuals
CURLOPT_TIMEOUT: set maximum time the request is allowed to take
NAMECURLOPT_TIMEOUT - set maximum time the request is allowed to take
DESCRIPTIONPass a long as parameter containing timeout - the maximum time in seconds that you allow the libcurl transfer operation to take. Normally, name lookups can take a considerable time and limiting operations to less than a few minutes risk aborting perfectly normal operations. This option may cause libcurl to use the SIGALRM signal to timeout system calls.
In unix-like systems, this might cause signals to be used unless CURLOPT_NOSIGNAL(3) is set.
Since this puts a hard limit for how long time a request is allowed to take, it has limited use in dynamic use cases with varying transfer times. You are then advised to explore CURLOPT_LOW_SPEED_LIMIT(3), CURLOPT_LOW_SPEED_TIME(3) or using CURLOPT_PROGRESSFUNCTION(3) to implement your own timeout logic.