Re: libc/printf bug

bill pursell wrote:
The following code exhibits unexpected behavior. Either it's
a bug in libc, or the author (me) is blind as a bat. Am I missing
something here, or is something horribly wrong? It appears
that printf is mangling the address unless the second argument
gets cast. I don't see that the cast should have any effect at all
on the output. Any thoughts?
There are quite a few errors in this code.
libc is not at fault.

1. Forgot to include <stdio.h>, this is important so
you get a proper prototye for printf, else the compiler
assumes all arguments are int - and who knows what happens
when it itsn't so, and the compiler generates wrong code
accroding to what you intended.

2. %x are not for printing floats.

[tmp]$ cat printf_bug.c


int
main()
{

float a=0;

printf("%p\n", &a);
printf("%x %p\n", a, &a);
printf("%x %p\n", (int)a, &a);
}
[tmp]$ ./a.out
0xfefb6764
0 (nil)
0 0xfefb6764
[tmp]$



--
Nils O. Selåsdal
www.utelsystems.com
.

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