From: Radical DOT NetSurfer AT delorie DOT com
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Please add strrev proposal
Date: Sat, 29 Sep 2001 00:36:07 -0400
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On Sat, 29 Sep 2001 00:28:28 GMT, CBFalconer <cbfalconer AT yahoo DOT com>
wrote:

>"A. Sinan Unur" wrote:
>> 
>> Radical NetSurfer wrote in
>> news:lcq8rtk1nqua2hc6rqfhmqisbd587n8t2n AT 4ax DOT com:
>> 
>> > I would like to encourage everyone who has a need for
>> > strrev to come forward and encourage the maintainers of
>> > LIBC used with GCC to kindly add   strrev.
>> 
>> Count me against this if for no other reason that the fact that I do not
>> like extra nonstandard function which solve tiny problems. If you need the
>> functionality, you can write one for your own situation. If it is going to
>> be added to a library, the solution needs to be useful to more than just
>> one person in a particular situation.
>> 
>> Anyway, the main point of my post, however, is to point out just one of the
>> gotchas with these kinds of functions.
>> 
>> You give the following usage example:
>> 
>> > Example
>> > printf("The reverse of %s is %s\n", str,  strrev(str) );
>> 
>> Hmmmmm  ..... let us see using the code you suggested:
>> 
>> /* +++Date last modified: 05-Jul-1997 */
>> /*
>> **  STRREV.C - reverse a string in place
>> **
>> **  public domain by Bob Stout
>> */
>> 
>> #include <string.h>
>> #include <stdlib.h>
>> #include <stdio.h>
>> 
>> char *strrev(char *str) {
>>         char *p1, *p2;
>> 
>>         if (! str || ! *str) return str;
>>         for (p1 = str, p2 = str + strlen(str) - 1; p2 > p1; ++p1, --p2)
>>         {
>>                 *p1 ^= *p2;
>>                 *p2 ^= *p1;
>>                 *p1 ^= *p2;
>>         }
>>         return str;
>> }
>> 
>> int main(void)
>> {
>>         char s[] = "This is a test.";
>>         printf("Original String: %s\nReversed String:%s\n", s, strrev(s));
>>         return 0;
>> }
>> 
>> C:\var>gcc djstrrev.c -o djstrrev.exe -O2 -Wall
>> 
>> C:\var>djstrrev
>> Original String: .tset a si sihT
>> Reversed String: .tset a si sihT

If your compiler actually outputs both strings as reversed,
THEN I am very scared your compiler is quite BROKEN.

printf("format specifier1, format_specififer2", var1, func1);
 
does:
display __current__ value of   var1 FIRST using format_specifier1,
__THEN__
display __output__ of  funct1 using format_specifier2,

If DJGPP is not doing even this trivial behavior correctly,
Borland programs would never port correctly,
neither would anything else for that matter.

Left to right, in the order AND STATE ENCOUNTERED!

....however... __AFTER__ the call to   printf(), __THEN__
'str' will contain the result of the function call;
but __NEVER__ from  __WITHIN__ the printf   as
you implied.  Your post is VERY MISLEADING.
 
>> Now, think about that.
>
>Thank you.  I knew there was a reason I made my equivalent
>(revstring) a void function.  I just didn't know what it was :-)