🚀 go-pugleaf

In article <X3NgqB3w164w@kryton.UUCP>,
system@kryton.UUCP (Scott Beckstead) writes:
|> I am currently porting a cygnus version of gcc (gpp objc etc.) to a new system.
|> In my libraries (ansi) strcmp return -1 for less than, 1 for greater than and
|> 0 for equality.  The spec merely states negative for less than positive for greater
|> than and 0 for equal.  Yet in the file rtl.c There is a code fragment that 
|> looks like this 
|> 
|> 	if(!strcmp(somevalue,someothervalue))
|> 		someaction;
|> 
|> This seems like a particularly BAD idea considering the values returned by
|> this fully ansi compliant library (yes it does change the behavior of
|> the programs)  I have modified my library to fix this but the code
|> really should be fixed so that a unary not of a non boolean return
|> is not used as a boolean.  Because with the value -1 I'm sure you see the
|> problem.  (!(-1) is 0 but !(1) is -2 and !(0) is -1) 

I think that you are confusing ! with ~ as I hope that this shows.

 eos6c02 tmp 11 > cat testcode.c
#include <stdio.h>

int main()
{
    int i;

    for ( i = -1; i <= 1; ++i)
        printf( "!(%2d) == %2d, ~(%2d) == %2d.\n", i, !i, i, ~i);
    
    return 0;
}
 eos6c02 tmp 12 > testcode
!(-1) ==  0, ~(-1) ==  0.
!( 0) ==  1, ~( 0) == -1.
!( 1) ==  0, ~( 1) == -2.

In C, 0 is false everything else is true.

-- 

Michael Salmon

#include	<standard.disclaimer>
#include	<witty.saying>
#include	<fancy.pseudo.graphics>

Ericsson Telecom AB
Stockholm

system@kryton.UUCP (Scott Beckstead) writes:

| Yet in the file rtl.c There is a code fragment that 
| looks like this 

| 	if(!strcmp(somevalue,someothervalue))
| 		someaction;

| This seems like a particularly BAD idea considering the values returned by
| this fully ansi compliant library (yes it does change the behavior of
| the programs)  I have modified my library to fix this but the code
| really should be fixed so that a unary not of a non boolean return
| is not used as a boolean.  Because with the value -1 I'm sure you see the
| problem.  (!(-1) is 0 but !(1) is -2 and !(0) is -1) 

What on earth are you talking about?  The "!" operator NEVER returns
ANYTHING but 0 or 1.  Maybe you're thinking about the "~" operator.

| I beleive the intent of this code to be:

|      if(!(strcmp(somevalue,someothervalue) == 0))
|              someaction;  

Well, you're wrong, and you've just introduced a bug.

-- 
"If you've got a pig that likes jumping fences, | robert earl
you have to make its fence a lot higher all at  | rearl@ucsd.edu
once -- if you do it by increments, all you're  | rearl@piggy.ucsb.edu
doing is training a jumping pig." -Henry Spencer|