What is the difference between '__asm' and '__asm__'?

Question

I am learning inline assembly in C. As far as I can tell, the only difference between __asm { ... }; and __asm__("..."); is that the first uses mov eax, var and the second uses movl %0, %%eax with :"=r" (var) at the end. Also, there are a lot less websites about the first. What other differences are there?

Answer 1

Which one you use depends on your compiler. This isn't standard like the C language.