gcc/g++ 4.8.2 won't convert uint64 to char properly.
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
gcc-4.8 (Ubuntu) |
New
|
Undecided
|
Unassigned |
Bug Description
I have an Ubuntu 14.04 system for arm7l (armhf), and I think
I have found a bug in the g++/gcc compiler.
I am expecting to see 'char c' below to end up as a negative number,
but as you can see, it does not. x86 system shows the negative number
as expected.
Anyone have any ideas for a work-around, or proper code if mine is
buggy?
greearb@
#include <stdlib.h>
#include <stdio.h>
int main() {
unsigned long long val = 0x8b;
char c = val;
printf("c: %d 0x%x\n", c, c);
return 0;
}
greearb@
greearb@
c: 139 0x8b
greearb@
greearb@
g++ (Ubuntu/Linaro 4.8.2-19ubuntu1) 4.8.2
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
On x86 system:
[greearb@ben-dt ~]$ g++ -o test test.cc
[greearb@ben-dt ~]$ ./test
c: -117 0xffffff8b
[greearb@ben-dt ~]$ gcc --version
gcc (GCC) 4.7.2 20121109 (Red Hat 4.7.2-8)
I don't think that's a bug. char is unsigned on ARM by default. Use signed char instead.