diff options
| -rw-r--r-- | 001help.cc | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/001help.cc b/001help.cc index 25dd27d5..a0241e95 100644 --- a/001help.cc +++ b/001help.cc @@ -113,7 +113,7 @@ void initialize_signal_handlers() { sigaction(SIGABRT, &action, NULL); // assert() failure or integer overflow on linux (with -ftrapv) sigaction(SIGILL, &action, NULL); // integer overflow on OS X (with -ftrapv) } -void dump_and_exit(int sig, siginfo_t* siginfo, unused void* dummy) { +void dump_and_exit(int sig, unused siginfo_t* dummy1, unused void* dummy2) { switch (sig) { case SIGABRT: #ifndef __APPLE__ @@ -134,6 +134,32 @@ void dump_and_exit(int sig, siginfo_t* siginfo, unused void* dummy) { :(before "End Includes") #include <signal.h> +//: For good measure we'll also enable SIGFPE. +:(before "atexit(teardown)") +feenableexcept(FE_OVERFLOW | FE_UNDERFLOW); +//? assert(sizeof(int) == 4 && sizeof(float) == 4); +//? // | exp | mantissa +//? int smallest_subnormal = 0b00000000000000000000000000000001; +//? float smallest_subnormal_f = *reinterpret_cast<int*>(&smallest_subnormal); +//? cerr << "ε/2: " << smallest_subnormal_f/2 << " (underflow)\n"; // test SIGFPE +:(before "End Includes") +#include <fenv.h> +:(code) +#ifdef __APPLE__ +// Public domain polyfill for feenableexcept on OS X +// http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c +inline int feenableexcept (unsigned int excepts) { + static fenv_t fenv; + unsigned int new_excepts = excepts & FE_ALL_EXCEPT; + unsigned int old_excepts; + if (fegetenv(&fenv)) return -1; + old_excepts = fenv.__control & FE_ALL_EXCEPT; + fenv.__control &= ~new_excepts; + fenv.__mxcsr &= ~(new_excepts << 7); + return fesetenv(&fenv) ? -1 : old_excepts; +} +#endif + //: 6. Map's operator[] being non-const is fucking evil. :(before "Globals") // can't generate prototypes for these // from http://stackoverflow.com/questions/152643/idiomatic-c-for-reading-from-a-const-map |