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FreeBSD/GCC Oddness.
- From: Chris Keladis <chris at cmc dot optus dot net dot au>
- To: gcc-help at gcc dot gnu dot org
- Date: Sat, 24 May 2003 20:35:26 +1000
- Subject: FreeBSD/GCC Oddness.
Hi folks,
On a FreeBSD 4.8-RC box with "gcc version 2.95.4 20020320 [FreeBSD]" i
have a question with how the compiler computes the space for local
variables on the stack.
Using the following sample code.
/* dummy program */
int func(void)
{
int i;
return(0);
}
int main(void)
{
func();
return(0);
}
Generates the following prologue (for func()) in GDB
0x804846c <func>: push %ebp
0x804846d <func+1>: mov %esp,%ebp
0x804846f <func+3>: sub $0x18,%esp
Why is 0x18 subtracted instead of 0x4? Alignment, performance? A RedHat
box with the same code sub's 0x4. I was wondering if some kind soul
could enlighten me on the reason for this?
Thanks,
Chris.