fay59

Here's a list of mildly interesting things about the C language that I learned mostly by consuming Clang's ASTs. Although surprises are getting sparser, I might continue to update this document over time.

There are many more mildly interesting features of C++, but the language is literally known for being weird, whereas C is usually considered smaller and simpler, so this is (almost) only about C.

1. Combined type and variable/field declaration, inside a struct scope [https://godbolt.org/g/Rh94Go]

struct foo {
   struct bar {
 int x;

Aegean-Homines

/*
  COMPARISON
  keylen = 512, iterations = 100000
====================================
            Simple... 0.078 s
                RS... 0.422 s
         RS (Fast)... 0.156 s
         Universal... 0.454 s
  Universal (Fast)... 0.156 s
               PJW... 0.328 s

XProger

uint32 blend(uint32 color1, uint32 color2, uint8 alpha) {
	uint32 rb = color1 & 0xff00ff;
	uint32 g  = color1 & 0x00ff00;
	rb += ((color2 & 0xff00ff) - rb) * alpha >> 8;
	g  += ((color2 & 0x00ff00) -  g) * alpha >> 8;
	return (rb & 0xff00ff) | (g & 0xff00);
}