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Bug #13339 sscanf returns wrong result
Submitted: 2001-09-17 05:50 UTC Modified: 2002-07-07 12:38 UTC
From: dev at generalprotectionfault dot de Assigned:
Status: Closed Package: Variables related
PHP Version: 4.0.6 OS: Windows NT 4.0
Private report: No CVE-ID: None
View Developer Edit
 [2001-09-17 05:50 UTC] dev at generalprotectionfault dot de 
I've tried this:

list($x) = sscanf( 'ac100000', '%x' );
printf("%x",$x);

And I got "7fffffff", weird.

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 [2001-09-17 05:53 UTC] derick@php.net 
This is not weird, PHP's int are signed integers. 0xac00000 is too large for that.

Derick
 [2001-09-18 02:34 UTC] derick@php.net 
Please use the Web system for answerring.

User update:
You said php4 uses signed integers, so please explain that:

// - - - - - - - - - - - - - - - - - -
list($x) = sscanf( 'ffffffff', '%x' );
printf("%x<br>",$x);

$x = pow(2,32)-1;
echo $x , "<br>";
$y = ( $x >> 16 ) & 0xFFFF ;
$x &= 0xFFFF;

printf("%x%x<br>",$y,$x);
// - - - - - - - - - - - - - - - - - -

Result:
7fffffff
4294967295
ffffffff
 [2001-09-18 02:35 UTC] derick@php.net 
This was my result (On linux):
7ffffff
4294967295
80000
 [2002-07-07 12:38 UTC] derick@php.net 
$x = pow(2,32)-1; var_dump ($x) will give this:

float(4294967295)

Which is not an integer, and thus the value can be larger than +(2^31 -1)

Anyway, this is not a bug, so closing.

Derick
 
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