#include <pcre.h>

int pcre_exec(const pcre *code,const pcre_extra *extra,const char *subject,intlength,intstartoffset,intoptions,int *ovector,intovecsize);

This function matches a compiled regular expression against a given subject string,using a matching algorithm that is similar to Perl's. It returns offsets to captured substrings. Its arguments are:

  code         Points to the compiled pattern
  extra        Points to an associated pcre[16|32]_extra structure,or is NULL
  subject      Points to the subject string
  length       Length of the subject string,in bytes
  startoffset  Offset in bytes in the subject at which to
                 start matching
  options      Option bits
  ovector      Points to a vector of ints for result offsets
  ovecsize     Number of elements in the vector (a multiple of 3)

上述的API介绍为Pcre官网的介绍，大致翻译为
该函数从给予的Subject中匹配一个编译后的正则表达式，使用和Perl相似的匹配算法。该函数返回匹配的子串的偏移量