[SOLVED] undefined reference to `stricmp'

Aquarius_Girl · 12-10-2010, 02:57 AM

junk.c

Code:

#include <string.h>

int main ()
{
     stricmp ("anisha", "kaul");
     return 0;
}

Code:

anisha@linux-uitj:~> gcc junk.c -Wall -Wextra
junk.c: In function ‘main’:
junk.c:5: warning: implicit declaration of function ‘stricmp’
/tmp/ccUhL95d.o: In function `main':
junk.c:(.text+0x14): undefined reference to `stricmp'
collect2: ld returned 1 exit status

The man page: http://www.qnx.com/developers/docs/6...s/stricmp.html
says it is in string.h, HELP!

eSelix · 12-10-2010, 03:37 AM

Try using instead strncasecmp()

Aquarius_Girl · 12-10-2010, 03:42 AM

Well, strncasecmp worked, thanks for that, but I am still wondering what happened to stricmp ???

wje_lq · 12-10-2010, 05:49 AM

The link you gave us pointed to a QNX man page. QNX is not Linux; you have shown us that QNX offers a function, stricmp(), which is not part of the POSIX standard.

sree_ec · 12-10-2010, 09:55 AM

Quote:

Originally Posted by anishakaul

junk.c

Code:

#include <string.h>

int main ()
{
     stricmp ("anisha", "kaul");
     return 0;
}

Code:

anisha@linux-uitj:~> gcc junk.c -Wall -Wextra
junk.c: In function ‘main’:
junk.c:5: warning: implicit declaration of function ‘stricmp’
/tmp/ccUhL95d.o: In function `main':
junk.c:(.text+0x14): undefined reference to `stricmp'
collect2: ld returned 1 exit status

The man page: http://www.qnx.com/developers/docs/6...s/stricmp.html
says it is in string.h, HELP!

If it were nt inside string.h, it should hv been a compiler error you were getting instead of linker error.
So you can look whether the definition is inside some Compiler directive[macros]

eSelix · 12-10-2010, 04:55 PM

Quote:

If it were nt inside string.h, it should hv been a compiler error

He got compiler warning first.

Quote:

junk.c:5: warning: implicit declaration of function ‘stricmp’

This means that function has not been declared ealier (even in string.h) and compiler did it automagically - but this was not been intention of programmer.

Aquarius_Girl · 12-12-2010, 09:01 PM

Quote:

Originally Posted by sree_ec

If it were nt inside string.h, it should hv been a compiler error you were getting instead of linker error.
So you can look whether the definition is inside some Compiler directive[macros]

Okay, look at the following code, I ve added another function:
junk.c

Code:

#include <string.h>

int main ()
{
     stricmp ("sad", "sdsa");
     unknown ();
     return 0;
}

Output:

Code:

anisha@linux-uitj:~> gcc junk.c -Wall -Wextra
junk.c: In function ‘main’:
junk.c:5: warning: implicit declaration of function ‘stricmp’
junk.c:6: warning: implicit declaration of function ‘unknown’
/tmp/cc8TuWnE.o: In function `main':
junk.c:(.text+0x14): undefined reference to `stricmp'
junk.c:(.text+0x1e): undefined reference to `unknown'
collect2: ld returned 1 exit status

Now whatdoyou say

Quote:

Originally Posted by eSelix

She got compiler warning first.

Aquarius_Girl · 12-12-2010, 09:31 PM

Quote:

Originally Posted by wje_lq

The link you gave us pointed to a QNX man page. QNX is not Linux; you have shown us that QNX offers a function, stricmp(), which is not part of the POSIX standard.

Thanks for pointing that out!
Now I looked up Goooooo to find out this:

Quote:

QNX is a commercial Unix-like real-time operating system, aimed primarily at the embedded systems market.

Secondly, I looked up /usr/src/linux-2.6.31.5-0.1/include/linux/string.h

I saw there a function named: strnicmp, which is not much different from stricmp!

Is there any link which contains all Posix standard functions?

Aquarius_Girl · 12-12-2010, 10:36 PM

I found this: http://en.wikipedia.org/wiki/String.h

Here strnicmp is missing in that link but it is present in string.h in my computer with OpenSuse 11.2 with the following declaration:
extern int strnicmp(const char *, const char *, __kernel_size_t);

Code:

#include <string.h>

int main ()
{
     strnicmp ("anisha", "kaul");
     return 0;
}

Code:

anisha@linux-uitj:~> gcc junk.c -Wall -Wextra
junk.c: In function ‘main’:
junk.c:5: warning: implicit declaration of function ‘strnicmp’
/tmp/ccI5NoIs.o: In function `main':
junk.c:(.text+0x14): undefined reference to `strnicmp'
collect2: ld returned 1 exit status

Code:

anisha@linux-uitj:~> man strnicmp

STRNICMP(9)                            Basic C Library Functions                           STRNICMP(9)



NAME
       strnicmp - Case insensitive, length-limited string comparison

SYNOPSIS
       int strnicmp(const char * s1, const char * s2, size_t len);

ARGUMENTS
       s1
           One string

       s2
           The other string

       len
           the maximum number of characters to compare

COPYRIGHT
Kernel Hackers Manual 2.6.

wje_lq · 12-12-2010, 10:45 PM

In the name of the Flying Spaghetti Monster,

You could return to google and search for "standard POSIX functions". That yields two very useful links near the top of the search, to wikipedia articles entitled "POSIX" and "C POSIX library". Browse through both of those; the second one contains this very useful link.

wje_lq · 12-12-2010, 10:50 PM

Quote:

Originally Posted by anishakaul

it is present in string.h in my computer with OpenSuse 11.2[/I][/U] with the following declaration:
extern int strnicmp(const char *, const char *, __kernel_size_t);

Hmmmm. "Present". You use that term. I do not think it means what you think it means. Is that line surrounded by any conditional compilation directives which end up excluding it?

Here's a test, if it's in fact your computer: Change that line in string.h so it says:

Code:

exxtern int strnicmp(const char *, const char *, __kernel_size_t);

That's right. Put an extra x in there. If your code still compiles, then this line was excluded by conditional compilation directives, so the compiler didn't care about that extra x. (Be sure to change it back, just because leaving a mess is not a good idea.)

Aquarius_Girl · 12-12-2010, 10:56 PM

Quote:

Originally Posted by wje_lq

Hmmmm. "Present". You use that term. I do not think it means what you think it means. Is that line surrounded by any conditional compilation directives which end up excluding it?

Thanks again for the useful link and comments! I don't know what has that monster to do with all this?? You write it most often, it is because the question was dumb?

I have attached the string.h and bolded the relevant text. I'll try out your way but why is the man page there then?

Code:

#ifndef _LINUX_STRING_H_
#define _LINUX_STRING_H_

/* We don't want strings.h stuff being used by user stuff by accident */

#ifndef __KERNEL__
#include <string.h>
#else

#include <linux/compiler.h>	/* for inline */
#include <linux/types.h>	/* for size_t */
#include <linux/stddef.h>	/* for NULL */
#include <stdarg.h>

extern char *strndup_user(const char __user *, long);
extern void *memdup_user(const void __user *, size_t);

/*
 * Include machine specific inline routines
 */
#include <asm/string.h>

#ifndef __HAVE_ARCH_STRCPY
extern char * strcpy(char *,const char *);
#endif
#ifndef __HAVE_ARCH_STRNCPY
extern char * strncpy(char *,const char *, __kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRLCPY
size_t strlcpy(char *, const char *, size_t);
#endif
#ifndef __HAVE_ARCH_STRCAT
extern char * strcat(char *, const char *);
#endif
#ifndef __HAVE_ARCH_STRNCAT
extern char * strncat(char *, const char *, __kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRLCAT
extern size_t strlcat(char *, const char *, __kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRCMP
extern int strcmp(const char *,const char *);
#endif
#ifndef __HAVE_ARCH_STRNCMP
extern int strncmp(const char *,const char *,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRNICMP
extern int strnicmp(const char *, const char *, __kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRCASECMP
extern int strcasecmp(const char *s1, const char *s2);
#endif
#ifndef __HAVE_ARCH_STRNCASECMP
extern int strncasecmp(const char *s1, const char *s2, size_t n);
#endif
#ifndef __HAVE_ARCH_STRCHR
extern char * strchr(const char *,int);
#endif
#ifndef __HAVE_ARCH_STRNCHR
extern char * strnchr(const char *, size_t, int);
#endif
#ifndef __HAVE_ARCH_STRRCHR
extern char * strrchr(const char *,int);
#endif
extern char * strstrip(char *);
#ifndef __HAVE_ARCH_STRSTR
extern char * strstr(const char *,const char *);
#endif
#ifndef __HAVE_ARCH_STRLEN
extern __kernel_size_t strlen(const char *);
#endif
#ifndef __HAVE_ARCH_STRNLEN
extern __kernel_size_t strnlen(const char *,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRPBRK
extern char * strpbrk(const char *,const char *);
#endif
#ifndef __HAVE_ARCH_STRSEP
extern char * strsep(char **,const char *);
#endif
#ifndef __HAVE_ARCH_STRSPN
extern __kernel_size_t strspn(const char *,const char *);
#endif
#ifndef __HAVE_ARCH_STRCSPN
extern __kernel_size_t strcspn(const char *,const char *);
#endif

#ifndef __HAVE_ARCH_MEMSET
extern void * memset(void *,int,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_MEMCPY
extern void * memcpy(void *,const void *,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_MEMMOVE
extern void * memmove(void *,const void *,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_MEMSCAN
extern void * memscan(void *,int,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_MEMCMP
extern int memcmp(const void *,const void *,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_MEMCHR
extern void * memchr(const void *,int,__kernel_size_t);
#endif

extern char *kstrdup(const char *s, gfp_t gfp);
extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
extern void *kmemdup(const void *src, size_t len, gfp_t gfp);

extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
extern void argv_free(char **argv);

extern bool sysfs_streq(const char *s1, const char *s2);

#ifdef CONFIG_BINARY_PRINTF
int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
#endif

extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
			const void *from, size_t available);

/**
 * strstarts - does @str start with @prefix?
 * @str: string to examine
 * @prefix: prefix to look for.
 */
static inline bool strstarts(const char *str, const char *prefix)
{
	return strncmp(str, prefix, strlen(prefix)) == 0;
}
#endif
#endif /* _LINUX_STRING_H_ */

wje_lq · 12-12-2010, 11:43 PM

In the name of the Flying Spaghetti Monster,

Here's your trouble. You're probably not including string.h, but rather strings.h. I'm glad you're posting its content; see this part?

Code:

/* We don't want strings.h stuff being used by user stuff by accident */

#ifndef __KERNEL__
#include <string.h>
#else

If in fact you're including strings.h, those lines in that file correct the error for you, and nothing else (see that else?) in the file will be accessible to you, including strnicmp.

Quote:

Originally Posted by anishakaul

why is the man page there then?

Excellent question. If you posted the entire man page, it omits a very important section: the CONFORMING TO section. Does your man page for strncasecmp have such a section? There's one in Debian's man page:

Code:

CONFORMING TO
       4.4BSD, POSIX.1-2001.

Quote:

Originally Posted by anishakaul

I don't know what has that monster to do with all this??

Happy to enlighten you. First, read all about the Flying Spaghetti Monster here. I started invoking its name after another poster, in asking a question, began his question in the name of Allah. Someone else objected, and a moderator stepped in, saying that we shouldn't be "making religious statements" in our posts. The moderator locked the thread. I suspect there's a certain amount of unintentional bias here, because nobody seems to be disciplined because of including (Christian) Bible quotations in his signature. I raised the issue with the moderator, asking whether we were going to be consistent, and got no answer. So I'm using this greeting to establish a precedent. Maybe they'll discipline me with ten lashes with a wet piece of spaghetti or something. (The normal English idiom for ridiculously mild punishment would be "ten lashes with a wet noodle".) For more information, go here and here and here.

eSelix · 12-13-2010, 05:36 PM

Quote:

Originally Posted by anishakaul

She got compiler warning first.

Sorry Anisha

I second time mistake someone gender. There should be some kind of sex mark near the nick.

Quote:

Okay, look at the following code, I ve added another function:
junk.c

Code:

#include <string.h>

int main ()
{
     stricmp ("sad", "sdsa");
     unknown ();
     return 0;
}

Now whatdoyou say

I could say the same as ealier

But I try to say that otherwise. In C every undeclared function, like unknown() and stricmp() is automaticaly declared during first occurrence by the compiler. It is declared but anywhere defined. So compiler generate a warning (implicit declaration of function) and linker an error (undefined reference to).

You can get better error handling if you use C++. It has more strict syntax. In your example it will generate compiler error just where is stricmp() that it wasn't anywhere declared.

sree_ec · 12-14-2010, 06:05 AM

Quote:

Originally Posted by anishakaul

Okay, look at the following code, I ve added another function:
junk.c

Code:

#include <string.h>

int main ()
{
     stricmp ("sad", "sdsa");
     unknown ();
     return 0;
}

Output:

Code:

anisha@linux-uitj:~> gcc junk.c -Wall -Wextra
junk.c: In function ‘main’:
junk.c:5: warning: implicit declaration of function ‘stricmp’
junk.c:6: warning: implicit declaration of function ‘unknown’
/tmp/cc8TuWnE.o: In function `main':
junk.c:(.text+0x14): undefined reference to `stricmp'
junk.c:(.text+0x1e): undefined reference to `unknown'
collect2: ld returned 1 exit status

Now whatdoyou say

I believe she was trying to correct me. Thank you anisha...Accepted. I did not pay much attention.