18 Language support library [language.support]

18.10 Other runtime support [support.runtime]

18.10.5 Header <csignal> synopsis [csignal.syn]

namespace std {
  using sig_atomic_t = see below;

  extern "C" using signal-handler = void(int);  // exposition only
  signal-handler* signal(int sig, signal-handler* func);

  int raise(int sig);
}

#define SIG_DFL see below
#define SIG_ERR see below
#define SIG_IGN see below
#define SIGABRT see below
#define SIGFPE see below
#define SIGILL see below
#define SIGINT see below
#define SIGSEGV see below
#define SIGTERM see below
1

The contents of the header <csignal> are the same as the C standard library header <signal.h>.

2

A call to the function signal synchronizes with any resulting invocation of the signal handler so installed.

3

The common subset of the C and C++ languages consists of all declarations, definitions, and expressions that may appear in a well formed C++ program and also in a conforming C program. A POF (“plain old function”) is a function that uses only features from this common subset, and that does not directly or indirectly use any function that is not a POF, except that it may use plain lock-free atomic operations. A plain lock-free atomic operation is an invocation of a function f from Clause [atomics], such that f is not a member function, and either f is the function atomic_is_lock_free, or for every atomic argument A passed to f, atomic_is_lock_free(A) yields true. All signal handlers shall have C linkage. The behavior of any function other than a POF used as a signal handler in a C++ program is implementation-defined.221

See also: ISO C 7.14.

221)

In particular, a signal handler using exception handling is very likely to have problems. Also, invoking std::exit may cause destruction of objects, including those of the standard library implementation, which, in general, yields undefined behavior in a signal handler (see [intro.execution]).