If onoff is 1, libcurl will not use any functions that install signal
handlers or any functions that cause signals to be sent to the process. This
option is here to allow multi-threaded unix applications to still set/use all
timeout options etc, without risking getting signals.
If this option is set and libcurl has been built with the standard name
resolver, timeouts will not occur while the name resolve takes place.
Consider building libcurl with the c-ares or threaded resolver backends to
enable asynchronous DNS lookups, to enable timeouts for name resolves without
the use of signals.
Setting CURLOPT_NOSIGNAL(3) to 1 makes libcurl NOT ask the system to
ignore SIGPIPE signals, which otherwise are sent by the system when trying to
send data to a socket which is closed in the other end. libcurl makes an
effort to never cause such SIGPIPEs to trigger, but some operating systems
have no way to avoid them and even on those that have there are some corner
cases when they may still happen, contrary to our desire. In addition, using
CURLAUTH_NTLM_WB authentication could cause a SIGCHLD signal to be