string2.h

它通过提供glibc兼容使得应用程序移植到较小的c 库时相当得容易. 它能够应用到带虚拟存储的Linux和uClinux上.在大多数带MMU部件的平台上为使它更加紧凑,它也能够编译成共享库.uClib

				     (__const char *) (s1))[1] - __s2[1]);    \
			if (l1 > 1 && __result == 0)			      \
			  {						      \
			    __result = (((__const unsigned char *)	      \
					 (__const char *) (s1))[2] - __s2[2]);\
			    if (l1 > 2 && __result == 0)		      \
			      __result = (((__const unsigned char *)	      \
					  (__const char *)  (s1))[3]	      \
					  - __s2[3]);			      \
			  }						      \
		      }							      \
		    __result; }))

# define __strcmp_gc(s1, s2, l2) \
  (__extension__ ({ __const unsigned char *__s1 =			      \
		      (__const unsigned char *) (__const char *) (s1);	      \
		    register int __result =				      \
		      __s1[0] - ((__const unsigned char *)		      \
				 (__const char *) (s2))[0];		      \
		    if (l2 > 0 && __result == 0)			      \
		      {							      \
			__result = (__s1[1]				      \
				    - ((__const unsigned char *)	      \
				       (__const char *) (s2))[1]);	      \
			if (l2 > 1 && __result == 0)			      \
			  {						      \
			    __result =					      \
			      (__s1[2] - ((__const unsigned char *)	      \
					  (__const char *) (s2))[2]);	      \
			    if (l2 > 2 && __result == 0)		      \
			      __result =				      \
				(__s1[3]				      \
				 - ((__const unsigned char *)		      \
				    (__const char *) (s2))[3]);		      \
			  }						      \
		      }							      \
		    __result; }))
#endif


/* Compare N characters of S1 and S2.  */
#ifndef _HAVE_STRING_ARCH_strncmp
# define strncmp(s1, s2, n)						      \
  (__extension__ (__builtin_constant_p (n)				      \
		  && ((__builtin_constant_p (s1)			      \
		       && strlen (s1) < ((size_t) (n)))			      \
		      || (__builtin_constant_p (s2)			      \
			  && strlen (s2) < ((size_t) (n))))		      \
		  ? strcmp (s1, s2) : strncmp (s1, s2, n)))
#endif


/* Return the length of the initial segment of S which
   consists entirely of characters not in REJECT.  */
#if !defined _HAVE_STRING_ARCH_strcspn || defined _FORCE_INLINES
# ifndef _HAVE_STRING_ARCH_strcspn
#  define strcspn(s, reject) \
  __extension__								      \
  ({ char __r0, __r1, __r2;						      \
     (__builtin_constant_p (reject) && __string2_1bptr_p (reject)	      \
      ? ((__r0 = ((__const char *) (reject))[0], __r0 == '\0')		      \
	 ? strlen (s)							      \
	 : ((__r1 = ((__const char *) (reject))[1], __r1 == '\0')	      \
	    ? __strcspn_c1 (s, __r0)					      \
	    : ((__r2 = ((__const char *) (reject))[2], __r2 == '\0')	      \
	       ? __strcspn_c2 (s, __r0, __r1)				      \
	       : (((__const char *) (reject))[3] == '\0'		      \
		  ? __strcspn_c3 (s, __r0, __r1, __r2)			      \
		  : strcspn (s, reject)))))				      \
		  : strcspn (s, reject)); })
# endif

__STRING_INLINE size_t __strcspn_c1 (__const char *__s, int __reject);
__STRING_INLINE size_t
__strcspn_c1 (__const char *__s, int __reject)
{
  register size_t __result = 0;
  while (__s[__result] != '\0' && __s[__result] != __reject)
    ++__result;
  return __result;
}

__STRING_INLINE size_t __strcspn_c2 (__const char *__s, int __reject1,
				     int __reject2);
__STRING_INLINE size_t
__strcspn_c2 (__const char *__s, int __reject1, int __reject2)
{
  register size_t __result = 0;
  while (__s[__result] != '\0' && __s[__result] != __reject1
	 && __s[__result] != __reject2)
    ++__result;
  return __result;
}

__STRING_INLINE size_t __strcspn_c3 (__const char *__s, int __reject1,
				     int __reject2, int __reject3);
__STRING_INLINE size_t
__strcspn_c3 (__const char *__s, int __reject1, int __reject2,
	      int __reject3)
{
  register size_t __result = 0;
  while (__s[__result] != '\0' && __s[__result] != __reject1
	 && __s[__result] != __reject2 && __s[__result] != __reject3)
    ++__result;
  return __result;
}
#endif


/* Return the length of the initial segment of S which
   consists entirely of characters in ACCEPT.  */
#if !defined _HAVE_STRING_ARCH_strspn || defined _FORCE_INLINES
# ifndef _HAVE_STRING_ARCH_strspn
#  define strspn(s, accept) \
  __extension__								      \
  ({ char __a0, __a1, __a2;						      \
     (__builtin_constant_p (accept) && __string2_1bptr_p (accept)	      \
      ? ((__a0 = ((__const char *) (accept))[0], __a0 == '\0')		      \
	 ? ((void) (s), 0)						      \
	 : ((__a1 = ((__const char *) (accept))[1], __a1 == '\0')	      \
	    ? __strspn_c1 (s, __a0)					      \
	    : ((__a2 = ((__const char *) (accept))[2], __a2 == '\0')	      \
	       ? __strspn_c2 (s, __a0, __a1)				      \
	       : (((__const char *) (accept))[3] == '\0'		      \
		  ? __strspn_c3 (s, __a0, __a1, __a2)			      \
		  : strspn (s, accept)))))				      \
      : strspn (s, accept)); })
# endif

__STRING_INLINE size_t __strspn_c1 (__const char *__s, int __accept);
__STRING_INLINE size_t
__strspn_c1 (__const char *__s, int __accept)
{
  register size_t __result = 0;
  /* Please note that __accept never can be '\0'.  */
  while (__s[__result] == __accept)
    ++__result;
  return __result;
}

__STRING_INLINE size_t __strspn_c2 (__const char *__s, int __accept1,
				    int __accept2);
__STRING_INLINE size_t
__strspn_c2 (__const char *__s, int __accept1, int __accept2)
{
  register size_t __result = 0;
  /* Please note that __accept1 and __accept2 never can be '\0'.  */
  while (__s[__result] == __accept1 || __s[__result] == __accept2)
    ++__result;
  return __result;
}

__STRING_INLINE size_t __strspn_c3 (__const char *__s, int __accept1,
				    int __accept2, int __accept3);
__STRING_INLINE size_t
__strspn_c3 (__const char *__s, int __accept1, int __accept2, int __accept3)
{
  register size_t __result = 0;
  /* Please note that __accept1 to __accept3 never can be '\0'.  */
  while (__s[__result] == __accept1 || __s[__result] == __accept2
	 || __s[__result] == __accept3)
    ++__result;
  return __result;
}
#endif


/* Find the first occurrence in S of any character in ACCEPT.  */
#if !defined _HAVE_STRING_ARCH_strpbrk || defined _FORCE_INLINES
# ifndef _HAVE_STRING_ARCH_strpbrk
#  define strpbrk(s, accept) \
  __extension__								      \
  ({ char __a0, __a1, __a2;						      \
     (__builtin_constant_p (accept) && __string2_1bptr_p (accept)	      \
      ? ((__a0 = ((__const char  *) (accept))[0], __a0 == '\0')		      \
	 ? ((void) (s), NULL)						      \
	 : ((__a1 = ((__const char *) (accept))[1], __a1 == '\0')	      \
	    ? strchr (s, __a0)						      \
	    : ((__a2 = ((__const char *) (accept))[2], __a2 == '\0')	      \
	       ? __strpbrk_c2 (s, __a0, __a1)				      \
	       : (((__const char *) (accept))[3] == '\0'		      \
		  ? __strpbrk_c3 (s, __a0, __a1, __a2)			      \
		  : strpbrk (s, accept)))))				      \
      : strpbrk (s, accept)); })
# endif

__STRING_INLINE char *__strpbrk_c2 (__const char *__s, int __accept1,
				     int __accept2);
__STRING_INLINE char *
__strpbrk_c2 (__const char *__s, int __accept1, int __accept2)
{
  /* Please note that __accept1 and __accept2 never can be '\0'.  */
  while (*__s != '\0' && *__s != __accept1 && *__s != __accept2)
    ++__s;
  return *__s == '\0' ? NULL : (char *) (size_t) __s;
}

__STRING_INLINE char *__strpbrk_c3 (__const char *__s, int __accept1,
				     int __accept2, int __accept3);
__STRING_INLINE char *
__strpbrk_c3 (__const char *__s, int __accept1, int __accept2,
	      int __accept3)
{
  /* Please note that __accept1 to __accept3 never can be '\0'.  */
  while (*__s != '\0' && *__s != __accept1 && *__s != __accept2
	 && *__s != __accept3)
    ++__s;
  return *__s == '\0' ? NULL : (char *) (size_t) __s;
}
#endif


/* Find the first occurrence of NEEDLE in HAYSTACK.  Newer gcc versions
   do this itself.  */
#if !defined _HAVE_STRING_ARCH_strstr && !__GNUC_PREREQ (2, 97)
# define strstr(haystack, needle) \
  (__extension__ (__builtin_constant_p (needle) && __string2_1bptr_p (needle) \
		  ? (((__const char *) (needle))[0] == '\0'		      \
		     ? (char *) (size_t) (haystack)			      \
		     : (((__const char *) (needle))[1] == '\0'		      \
			? strchr (haystack,				      \
				  ((__const char *) (needle))[0]) 	      \
			: strstr (haystack, needle)))			      \
		  : strstr (haystack, needle)))
#endif


#if !defined _HAVE_STRING_ARCH_strtok_r || defined _FORCE_INLINES
# ifndef _HAVE_STRING_ARCH_strtok_r
#  define __strtok_r(s, sep, nextp) \
  (__extension__ (__builtin_constant_p (sep) && __string2_1bptr_p (sep)	      \
		  ? (((__const char *) (sep))[0] != '\0'		      \
		     && ((__const char *) (sep))[1] == '\0'		      \
		     ? __strtok_r_1c (s, ((__const char *) (sep))[0], nextp)  \
		     : __strtok_r (s, sep, nextp))			      \
		  : __strtok_r (s, sep, nextp)))
# endif

__STRING_INLINE char *__strtok_r_1c (char *__s, char __sep, char **__nextp);
__STRING_INLINE char *
__strtok_r_1c (char *__s, char __sep, char **__nextp)
{
  char *__result;
  if (__s == NULL)
    __s = *__nextp;
  while (*__s == __sep)
    ++__s;
  __result = NULL;
  if (*__s != '\0')
    {
      __result = __s++;
      while (*__s != '\0')
	if (*__s++ == __sep)
	  {
	    __s[-1] = '\0';
	    break;
	  }
      *__nextp = __s;
    }
  return __result;
}
# if defined __USE_POSIX || defined __USE_MISC
#  define strtok_r(s, sep, nextp) __strtok_r (s, sep, nextp)
# endif
#endif


#if !defined _HAVE_STRING_ARCH_strsep || defined _FORCE_INLINES
# ifndef _HAVE_STRING_ARCH_strsep

extern char *__strsep_g (char **__stringp, __const char *__delim);
#  define __strsep(s, reject) \
  __extension__								      \
  ({ char __r0, __r1, __r2;						      \
     (__builtin_constant_p (reject) && __string2_1bptr_p (reject)	      \
      && (__r0 = ((__const char *) (reject))[0],			      \
	  ((__const char *) (reject))[0] != '\0')			      \
      ? ((__r1 = ((__const char *) (reject))[1],			      \
	 ((__const char *) (reject))[1] == '\0')			      \
	 ? __strsep_1c (s, __r0)					      \
	 : ((__r2 = ((__const char *) (reject))[2], __r2 == '\0')	      \
	    ? __strsep_2c (s, __r0, __r1)				      \
	    : (((__const char *) (reject))[3] == '\0'			      \
	       ? __strsep_3c (s, __r0, __r1, __r2)			      \
	       : __strsep_g (s, reject))))				      \
      : __strsep_g (s, reject)); })
# endif

__STRING_INLINE char *__strsep_1c (char **__s, char __reject);
__STRING_INLINE char *
__strsep_1c (char **__s, char __reject)
{
  register char *__retval = *__s;
  if (__retval != NULL && (*__s = strchr (__retval, __reject)) != NULL)
    *(*__s)++ = '\0';
  return __retval;
}

__STRING_INLINE char *__strsep_2c (char **__s, char __reject1, char __reject2);
__STRING_INLINE char *
__strsep_2c (char **__s, char __reject1, char __reject2)
{
  register char *__retval = *__s;
  if (__retval != NULL)
    {
      register char *__cp = __retval;
      while (1)
	{
	  if (*__cp == '\0')
	    {
	      __cp = NULL;
	  break;
	    }
	  if (*__cp == __reject1 || *__cp == __reject2)
	    {
	      *__cp++ = '\0';
	      break;
	    }
	  ++__cp;
	}
      *__s = __cp;
    }
  return __retval;
}

__STRING_INLINE char *__strsep_3c (char **__s, char __reject1, char __reject2,
				   char __reject3);
__STRING_INLINE char *
__strsep_3c (char **__s, char __reject1, char __reject2, char __reject3)
{
  register char *__retval = *__s;
  if (__retval != NULL)
    {
      register char *__cp = __retval;
      while (1)
	{
	  if (*__cp == '\0')
	    {
	      __cp = NULL;
	  break;
	    }
	  if (*__cp == __reject1 || *__cp == __reject2 || *__cp == __reject3)
	    {
	      *__cp++ = '\0';
	      break;
	    }
	  ++__cp;
	}
      *__s = __cp;
    }
  return __retval;
}
# ifdef __USE_BSD
#  define strsep(s, reject) __strsep (s, reject)
# endif
#endif

/* We need the memory allocation functions for inline strdup().
   Referring to stdlib.h (even minimally) is not allowed
   in any of the tight standards compliant modes.  */
#ifdef __USE_MISC

# if !defined _HAVE_STRING_ARCH_strdup || !defined _HAVE_STRING_ARCH_strndup
#  define __need_malloc_and_calloc
#  include <stdlib.h>
# endif

# ifndef _HAVE_STRING_ARCH_strdup

extern char *__strdup (__const char *__string) __THROW __attribute_malloc__;
#  define __strdup(s) \
  (__extension__ (__builtin_constant_p (s) && __string2_1bptr_p (s)	      \
		  ? (((__const char *) (s))[0] == '\0'			      \
		     ? (char *) calloc (1, 1)				      \
		     : ({ size_t __len = strlen (s) + 1;		      \
			  char *__retval = (char *) malloc (__len);	      \
			  if (__retval != NULL)				      \
			    __retval = (char *) memcpy (__retval, s, __len);  \
			  __retval; }))					      \
		  : __strdup (s)))

#  if defined __USE_SVID || defined __USE_BSD || defined __USE_XOPEN_EXTENDED
#   define strdup(s) __strdup (s)
#  endif
# endif

# ifndef _HAVE_STRING_ARCH_strndup

extern char *__strndup (__const char *__string, size_t __n)
     __THROW __attribute_malloc__;
#  define __strndup(s, n) \
  (__extension__ (__builtin_constant_p (s) && __string2_1bptr_p (s)	      \
		  ? (((__const char *) (s))[0] == '\0'			      \
		     ? (char *) calloc (1, 1)				      \
		     : ({ size_t __len = strlen (s) + 1;		      \
			  size_t __n = (n);				      \
			  char *__retval;				      \
			  if (__n < __len)				      \
			    __len = __n + 1;				      \
			  __retval = (char *) malloc (__len);		      \
			  if (__retval != NULL)				      \
			    {						      \
			      __retval[__len - 1] = '\0';		      \
			      __retval = (char *) memcpy (__retval, s,	      \
							  __len - 1);	      \
			    }						      \
			  __retval; }))					      \
		  : __strndup (s, n)))

#  ifdef __USE_GNU
#   define strndup(s, n) __strndup (s, n)
#  endif
# endif

#endif /* Use misc. or use GNU.  */

#ifndef _FORCE_INLINES
# undef __STRING_INLINE
#endif

#endif /* No string inlines.  */