why this programme fail to compile

[sysabod]

Hi all:
i encounter this somewhat awkward define directive and could not figure out how to resolve this,please help me.

#include <stdio.h>
#include <assert.h>
static unsigned int test_endian_int = 0xdeadbeef;
enum endianess
{
	LITTLE,
	BIG,	
};

#define ENDIANNESS ( *(const char *)&test_endian_int == 0xef ? LITTLE \
                   : *(const char *)&test_endian_int == 0xde ? BIG \
                   : assert(0))

int main(int argc, char *argv[])
{
	enum endianess  this_endian = ENDIANNESS;
	if(this_endian == LITTLE) printf("little endian\n");

	return 0;
}

In function 'main':
Line 16: warning: comparison is always false due to limited range of data type
Line 16: warning: comparison is always false due to limited range of data type
Line 16: error: void value not ignored as it ought to be

Thanks in advance!

[Disch]

2 problems:

1) you probalby should be casting to const unsigned char*. Since chars are signed and 0xef is unsigned, the comparison will always be false.

2) By putting assert() in your ENDIANNESS macro, there is a possibility that it will have the following effect:

enum endianess = assert(0);  // this will happen if neither big or little endian 

Since assert returns a void, this is nonsense, hence why you're getting the error.