1  #include <stdint.h>
       2  
       3  #define STACK_CHK_GUARD \
       4    ({ uintptr_t x;						\
       5       asm ("mov %%fs:%c1, %0" : "=r" (x)				\
       6  	  : "i" (offsetof (tcbhead_t, stack_guard))); x; })
       7  
       8  #define POINTER_CHK_GUARD \
       9    ({ uintptr_t x;						\
      10       asm ("mov %%fs:%c1, %0" : "=r" (x)				\
      11  	  : "i" (offsetof (tcbhead_t, pointer_guard))); x; })