Code below produces incorrect output (seems that code generator makes invalid code, since nothing is changed when compiling with -o-all):
  a.pos = A;
  b.pos = 1234567890A;
But clearly, these values should be identical; Due to this bug I can't use bitfields for int64 in structure.

Nic Tiger.


dmc int64_bug.cpp
----------------------
#include <stdio.h>
#include <stdint.h>

struct A {
  uint64_t pos: 36;
};
struct B {
  uint64_t pos;
};

int main() {
  A a;
  B b;
  a.pos = 0x1234567890A;
  b.pos = 0x1234567890A;
  printf ( "a.pos=%llX\n", a.pos );
  printf ( "b.pos=%llX\n", b.pos );

  return 0;
}

Nic Tiger wrote:
> Code below produces incorrect output (seems that code generator makes invalid code, since nothing is changed when compiling with -o-all):
>   a.pos = A;
>   b.pos = 1234567890A;
> But clearly, these values should be identical; Due to this bug I can't use bitfields for int64 in structure.

ugh....

just came across "9.6-1 Bit Fields" section in DMC C++ language implementation / Implementation-defined Behavior.

so, bit fields larger than 32 bit (word size) are not allowed.
though, it would be nice if compiler emitted error about that...

Nic Tiger.