The signalrecovery from dhatbj

Dead loop caused by sa_sigaction being NULL

Hello, I'm confused about one part of the project. After using sigaction(sig, &action_info, &old_sa[sig]) in the function signal_handler_init(), I found that the values of old_sa[sig].sa_handler or old_sa[sig].sa_sigaction is always 0, which will leads to a problem: when initialized with signal_catch_init(), if a signal generated outside the try-catch range is caught, it should reasonably be handled according to the default logic, but the default handler function obtained through the sigaction function is NULL, so the signal_handler function cannot correctly handle This can lead to a dead loop where the exception is constantly triggered and signal_handler keeps catching.

catch signals from other threads

Does try...ctach catch signals(like sigkill) from other threads, and does this mean a misjudgment

Linker Error when Compiling Example

$ g++ main.cpp

Undefined symbols for architecture x86_64:
  "std::__1::locale::use_facet(std::__1::locale::id&) const", referenced from:
      std::__1::ctype<char> const& std::__1::use_facet<std::__1::ctype<char> >(std::__1::locale const&) in main-a884c1.o
  "std::__1::ios_base::getloc() const", referenced from:
      std::__1::basic_ios<char, std::__1::char_traits<char> >::widen(char) const in main-a884c1.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__init(unsigned long, char)", referenced from:
      std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(unsigned long, char) in main-a884c1.o
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::~basic_string()", referenced from:
      std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> > std::__1::__pad_and_output<char, std::__1::char_traits<char> >(std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> >, char const*, char const*, char const*, std::__1::ios_base&, char) in main-a884c1.o
  "std::__1::basic_ostream<char, std::__1::char_traits<char> >::put(char)", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::endl<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&) in main-a884c1.o
  "std::__1::basic_ostream<char, std::__1::char_traits<char> >::flush()", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::endl<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&) in main-a884c1.o
  "std::__1::basic_ostream<char, std::__1::char_traits<char> >::sentry::sentry(std::__1::basic_ostream<char, std::__1::char_traits<char> >&)", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long) in main-a884c1.o
  "std::__1::basic_ostream<char, std::__1::char_traits<char> >::sentry::~sentry()", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long) in main-a884c1.o
  "std::__1::cout", referenced from:
      _main in main-a884c1.o
  "std::__1::ctype<char>::id", referenced from:
      std::__1::ctype<char> const& std::__1::use_facet<std::__1::ctype<char> >(std::__1::locale const&) in main-a884c1.o
  "std::__1::locale::~locale()", referenced from:
      std::__1::basic_ios<char, std::__1::char_traits<char> >::widen(char) const in main-a884c1.o
  "std::__1::ios_base::__set_badbit_and_consider_rethrow()", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long) in main-a884c1.o
  "std::__1::ios_base::clear(unsigned int)", referenced from:
      std::__1::ios_base::setstate(unsigned int) in main-a884c1.o
  "std::terminate()", referenced from:
      ___clang_call_terminate in main-a884c1.o
  "___cxa_begin_catch", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long) in main-a884c1.o
      ___clang_call_terminate in main-a884c1.o
  "___cxa_call_unexpected", referenced from:
      std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> >::ostreambuf_iterator(std::__1::basic_ostream<char, std::__1::char_traits<char> >&) in main-a884c1.o
  "___cxa_end_catch", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long) in main-a884c1.o
  "___gxx_personality_v0", referenced from:
      std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long) in main-a884c1.o
      std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> > std::__1::__pad_and_output<char, std::__1::char_traits<char> >(std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> >, char const*, char const*, char const*, std::__1::ios_base&, char) in main-a884c1.o
      std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> >::ostreambuf_iterator(std::__1::basic_ostream<char, std::__1::char_traits<char> >&) in main-a884c1.o
      std::__1::basic_ios<char, std::__1::char_traits<char> >::widen(char) const in main-a884c1.o
      Dwarf Exception Unwind Info (__eh_frame) in main-a884c1.o
  "_env_buf_alloc", referenced from:
      _main in main-a884c1.o
  "_env_buf_get", referenced from:
      _main in main-a884c1.o
  "_env_buf_pop", referenced from:
      _main in main-a884c1.o
  "_env_buf_push", referenced from:
      _main in main-a884c1.o
  "_signal_catch_init", referenced from:
      _main in main-a884c1.o
  "_signal_info", referenced from:
      _main in main-a884c1.o
  "_signal_name", referenced from:
      _main in main-a884c1.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Did I miss an required option when compiling this?

Environment and Tool Versions

$ g++ --version

Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/usr/include/c++/4.2.1
Apple LLVM version 10.0.1 (clang-1001.0.46.4)
Target: x86_64-apple-darwin18.5.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

$ uname -a

Darwin Aarons-MacBook-Pro.local 18.5.0 Darwin Kernel Version 18.5.0: Mon Mar 11 20:40:32 PDT 2019; root:xnu-4903.251.3~3/RELEASE_X86_64 x86_64

Running macOS 10.14.4.

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signalrecovery's Issues

Dead loop caused by sa_sigaction being NULL

catch signals from other threads

Linker Error when Compiling Example

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