mc -> do (wy)znawcow C ;)

[Wojtek Slusarczyk]

Hej,
	W "Polnocnym Komandorze" jest sobie src/mountlist.c w ktorym w
linni 105 stoi:

char *strstr (const char *haystack, const char *needle);
/* void error (void);  FIXME -- needed? */

Podczas kompilacji na glibcu pluje takim bledem :

mountlist.c:105: parse error before `__extension__'
mountlist.c:105: parse error before `needle'
mountlist.c:105: initializer element is not constant
mountlist.c:105: warning: data definition has no type or storage class
mountlist.c:105: parse error before `needle'
mountlist.c:105: warning: data definition has no type or storage class
mountlist.c:105: parse error before `size_t'
make: *** [mountlist.o] Error 1

Zagladamy do <string.h> i widzimy:

/* Find the first occurrence of NEEDLE in HAYSTACK.  */
extern char *strstr __P ((__const char *__haystack, __const char *__needle));

#ifdef __USE_GNU
/* Similar to `strstr' but this function ignores the case of both strings.  */
extern char *__strcasestr __P ((__const char *__haystack,
				__const char *__needle));
extern char *strcasestr __P ((__const char *__haystack,
			      __const char *__needle));
#endif

Co wiecej w <bits/string.h> stoi:

/* Find the first occurrence of NEEDLE in HAYSTACK.  */
#define _HAVE_STRING_ARCH_strstr 1
#define strstr(haystack, needle) \
  (__extension__ (__builtin_constant_p (needle) && sizeof ((needle)[0]) == 1  \
		  ? ((needle)[0] == '\0'				      \
		     ? haystack						      \
		     : ((needle)[1] == '\0'				      \
			? strchr (haystack, (needle)[0])		      \
			: __strstr_cg (haystack, needle, strlen (needle))))   \
		  : __strstr_g (haystack, needle)))

/* Please note that this function need not handle NEEDLEs with a
   length shorter than two.  */
__STRING_INLINE char *
__strstr_cg (__const char *__haystack, __const char __needle[],
	     size_t __needle_len)
{
  register unsigned long int __d0, __d1, __d2;
  register char *__res;
  __asm__ __volatile__
    ("cld\n" \
     "1:\n\t"
     "movl	%6,%%edi\n\t"
     "movl	%5,%%eax\n\t"
     "movl	%4,%%ecx\n\t"
     "repe; cmpsb\n\t"
     "je	2f\n\t"
     "cmpb	$0,-1(%%esi)\n\t"
     "leal	1(%%eax),%5\n\t"
     "jne	1b\n\t"
     "xorl	%%eax,%%eax\n"
     "2:"
     : "=a" (__res), "=&S" (__d0), "=&D" (__d1), "=&c" (__d2)
     : "g" (__needle_len), "1" (__haystack), "d" (__needle)
     : "cc");
  return __res;
}

#ifdef __PIC__
__STRING_INLINE char *
__strstr_g (__const char *__haystack, __const char *__needle)
{
  register unsigned long int __d0, __d1, __d2;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "pushl	%%ebx\n\t"
     "decl	%%ecx\n\t"	/* NOTE! This also sets Z if searchstring='' */
     "movl	%%ecx,%%ebx\n"
     "1:\n\t"
     "movl	%%edx,%%edi\n\t"
     "movl	%%esi,%%eax\n\t"
     "movl	%%ebx,%%ecx\n\t"
     "repe; cmpsb\n\t"
     "je	2f\n\t"		/* also works for empty string, see above */
     "cmpb	$0,-1(%%esi)\n\t"
     "leal	1(%%eax),%%esi\n\t"
     "jne	1b\n\t"
     "xorl	%%eax,%%eax\n"
     "2:\n\t"
     "popl	%%ebx"
     : "=a" (__res), "=&c" (__d0), "=&S" (__d1), "=&D" (__d2)
     : "0" (0), "1" (0xffffffff), "2" (__haystack), "3" (__needle),
       "d" (__needle)
     : "cc");
  return __res;
}
#else
__STRING_INLINE char *
__strstr_g (__const char *__haystack, __const char *__needle)
{
  register unsigned long int __d0, __d1, __d2, __d3;
  register char *__res;
  __asm__ __volatile__
    ("cld\n\t"
     "repne; scasb\n\t"
     "notl	%%ecx\n\t"
     "decl	%%ecx\n\t"	/* NOTE! This also sets Z if searchstring='' */
     "movl	%%ecx,%%edx\n"
     "1:\n\t"
     "movl	%%ebx,%%edi\n\t"
     "movl	%%esi,%%eax\n\t"
     "movl	%%edx,%%ecx\n\t"
     "repe; cmpsb\n\t"
     "je	2f\n\t"		/* also works for empty string, see above */
     "cmpb	$0,-1(%%esi)\n\t"
     "leal	1(%%eax),%%esi\n\t"
     "jne	1b\n\t"
     "xorl	%%eax,%%eax\n"
     "2:"
     : "=a" (__res), "=&c" (__d0), "=&S" (__d1), "=&D" (__d2), "=&d" (__d3)
     : "0" (0), "1" (0xffffffff), "2" (__haystack), "3" (__needle),
       "b" (__needle)
     : "cc");
  return __res;
}
#endif

I teraz pytanie do wszystkich GURU: jak ustawic to diabelstwo za
wylaczeniem skrajnosci ???:

#if !((__GLIBC__ == 2) && (__GLIBC_MINOR__ >= 1))
char *strstr (const char *haystack, const char *needle);
#endif /* fix me fix me, please ... */

Wszelkie odpowiedzi nawet bledne mile widziane ..;)

Wojciech Slusarczyk (091)4494148
Technical University of Szczecin
PGP KeyServer pgpkeys.mit.edu