RE_NMATCH
static regmatch_t regex_match[RE_NMATCH];
if (num >= RE_NMATCH)
RE_NMATCH, regex_match, re_flags);
RE_NMATCH, regex_match, REG_STARTEND) &&
RE_NMATCH, regex_match, REG_STARTEND);
RE_NMATCH, regex_match, REG_STARTEND);