Running inline assembly code in C

#include <stdio.h>  void main() { const char *hello = "Hello, World!\n"; asm( "mov $1, %%rax\n" "mov $1, %%rdi\n" "mov %0, %%rsi\n" "mov $14, %%rdx\n" "syscall\n" : : "r"(hello) : "%rax", "%rdi", "%rsi", "%rdx" ); }