curl raise 信号出core

在使用c++多线程使用libcurl抓取网页时，遇到程序随机core掉的情况，gdb 一下出错信息有这么一条：longjmp causes uninitialized stack frame。

在网上查了一下原来是curl有“CURLOPT_NOSIGNAL” ，将这个值设为1就忽略抛出的信号了~

具体解释：

CURLOPT_NOSIGNAL

Pass a long. If it 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 mainly here to allow multi-threaded unix applications to still set/use all timeout options etc, without risking getting signals. The default value for this parameter is 0. (Added in 7.10)

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 c-ares support to enable asynchronous DNS lookups, which enables nice timeouts for name resolves without signals.

Setting CURLOPT_NOSIGNAL 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