On 2016-07-15 22:15, Alan Third wrote:
> Eli, I just wanted to run this by you because you wrote this code and
> I'm not sure if that =- is just a typo or it's something I've never
> seen before. My guess is it's a typo and gcc happily treats it as -=,
> but clang handles it more like 'y = y - a - b' resulting in odd
> behaviour on OS X.

In fact, both Clang and GCC treat it the same (as '=' followed by a unary minus):

#include <stdio.h>

int main () {
  int y = 1;
  y =- 1; // Same as y = -1;
  printf("%d\n", y); // Prints "-1"
}

Interestingly, clang warns about this:

    5   5 warning         use of unary operator that may be intended as compound assignment (-=) (c/c++-clang)

Thanks for spotting it!
Clément.