21 Language support library [language.support]

21.11 Other runtime support [support.runtime]

21.11.2 Header <csetjmp> synopsis [csetjmp.syn]

namespace std {
  using jmp_buf = see below;
  [[noreturn]] void longjmp(jmp_buf env, int val);
}

#define setjmp(env) see below
The contents of the header <csetjmp> are the same as the C standard library header <setjmp.h>.
The function signature longjmp(jmp_­buf jbuf, int val) has more restricted behavior in this document.
A setjmp/longjmp call pair has undefined behavior if replacing the setjmp and longjmp by catch and throw would invoke any non-trivial destructors for any automatic objects.
See also: ISO C 7.13