https://stackoverflow.com/questions/73425423/why-pcre-regex-only-capture-19-groups/73425562#73425562StackOverFlow 上面有老哥回复我了,这个问题还真没注意到,result 的长度需要 (group 个数 + 1) * 3
> The first two-thirds of the vector is used to pass back captured substrings, each substring using a pair of integers. The remaining third of the vector is used as workspace by pcre_exec() while matching capturing subpatterns, and is not available for passing back information. The number passed in ovecsize should always be a multiple of three. If it is not, it is rounded down.