#define UC_FP_XSTATE 0x1 /* indicates the presence of extended state * information in the memory layout pointed * by the fpstate pointer in the ucontext's * sigcontext struct (uc_mcontext). */
structucontext{unsignedlonguc_flags;structucontext*uc_link;stack_tuc_stack;structsigcontextuc_mcontext;sigset_tuc_sigmask;/* mask last for extensibility */};