gar::debug Namespace Reference

Classes
struct	CallInfo_t
	Structure with information about a single call, parsed. More...
class	CallInfoPrinter
	Class handling the output of information in a CallInfo_t object. More...

Functions
template<typename T >
std::string	demangle (T const *=nullptr)
	Outputs a demangled name for type T. More...
template<typename Stream >
Stream &	operator<< (Stream &&out, CallInfo_t const &info)
	Helper operator to insert a call information in a stream with default options. More...
template<typename Stream >
void	printBacktrace (Stream &&out, unsigned int maxLines=5, std::string indent=" ", CallInfoPrinter::opt const *options=nullptr)
	Prints the full backtrace into a stream. More...

Function Documentation

template<typename T >

std::string gar::debug::demangle ( T const *  = nullptr )

inline

Outputs a demangled name for type T.

---

Parameters

T	type whose name must be demangled (optional)

Returns

a string with demangled name

It relies on cetlib. The type to be demangled can be specified either as template argument:

auto name = gar::debug::demangle<std::string>();

or via a argument pointer:

auto name = gar::debug::demangle(this);

Definition at line 56 of file DebugUtils.h.

      { return cet::demangle_symbol(typeid(std::decay_t<T>).name()); }

template<typename Stream >

Stream& gar::debug::operator<< ( Stream &&  out, CallInfo_t const &  info  )

inline

Helper operator to insert a call information in a stream with default options.

Definition at line 229 of file DebugUtils.h.

      {
        CallInfoPrinter print;
        print(std::forward<Stream>(out), info);
        return out;
      }

template<typename Stream >

void gar::debug::printBacktrace	(	Stream &&	out,
		unsigned int	maxLines = 5,
		std::string	indent = "  ",
		CallInfoPrinter::opt const *	options = nullptr
	)

Prints the full backtrace into a stream.

Template Parameters

Stream

type of output stream

Parameters

out	the output stream to insert output into
maxLines	print at most this many lines in the output (default: 5)
indent	prepend a string in front of any new line (default: " ")
options	use these output options (default ones if null pointer)

The output options are described in CallInfo_t::opt structure.

Definition at line 249 of file DebugUtils.h.

    {
      constexpr unsigned int nSkip = 1;
      std::vector<void*> buffer(nSkip + std::max(maxLines, 200U), nullptr);
      
      unsigned int nItems
        = (unsigned int) backtrace(buffer.data(), buffer.size());
      
      // convert the calls in the buffer into a vector of strings
      char** symbols = backtrace_symbols(buffer.data(), buffer.size());
      if (!symbols) {
        out << indent << "<failed to get the call stack>" << std::endl;
      }
      std::vector<CallInfo_t> callStack;
      for (size_t i = 0; i < buffer.size(); ++i)
      callStack.push_back((const char*) symbols[i]);
      std::free(symbols);
      
      size_t lastItem = nSkip + maxLines;
      if (lastItem > nItems) lastItem = nItems;
      if (lastItem >= buffer.size()) --lastItem;
      
      CallInfoPrinter print;
      if (options) print.setOptions(*options);
      for (size_t i = nSkip; i < lastItem; ++i) {
        out << indent;
        print(std::forward<Stream>(out), callStack[i]);
        out << "\n";
      }
      if (lastItem < nItems) {
        out << indent << " ... and other " << (nItems - lastItem);
        if (nItems == buffer.size()) out << " (or more)";
        out << " levels\n";
      }
      out << std::flush;
      
    } // printBacktrace()