text: //#include <string.h>
  typedef unsigned long size_t;
  void *memcpy(void *buf1, const void *buf2, size_t n);
  int memcmp( const void *str1 , const void *str2, size_t len );
  size_t strlen( const char *str );
  void *memchr(const void *s,int c,size_t n);
  void *memset(void *s, int c, size_t n);
  