The _ _setjmp intrinsic has the following declaration:
int __setjmp( jmp_buf buffer );
When used in conjunction with longjmp, this intrinsic function provides a way to execute a nonlocal goto. To obtain the correct intrinsic definition of _ _setjmp for Alpha, you must use #include <setjmp.h> or <setjmpex.h>. Correct interaction with C structured exception handling and C++ exception-handling extensions requires the use of #include <setjmpex.h>.