logging.hxx

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///
/// Basic logging utilities meant to be used by binaries.
/// Use instead of RLogger for user-facing messages.
///
#ifndef ROOT_Main_Logging
#define ROOT_Main_Logging
 
#include <iostream>
 
namespace Detail {
 
class NullBuf : public std::streambuf {
public:
   int overflow(int c) final { return c; }
};
 
// A stream that discards all input.
class NullStream : public std::ostream {
   NullBuf fBuf;
 
public:
   NullStream() : std::ostream(&fBuf) {}
};
 
inline const char *gLogName = "";
/// Log verbosity works this way:
/// If it's <= 0, all warnings are suppressed.
/// Additionally, when Info(lv) is called, it is only displayed if lv <= LogVerbosity.
inline int gLogVerbosity = 1;
 
inline NullStream &GetNullStream()
{
   static NullStream nullStream;
   return nullStream;
}
 
} // namespace Detail
 
inline void InitLog(const char *name, int defaultVerbosity = 1)
{
   Detail::gLogName = name;
   Detail::gLogVerbosity = defaultVerbosity;
}
 
inline void SetLogVerbosity(int verbosity)
{
   Detail::gLogVerbosity = verbosity;
}
 
inline int GetLogVerbosity()
{
   return Detail::gLogVerbosity;
}
 
inline std::ostream &Err()
{
   std::cerr << "Error in <" << Detail::gLogName << ">: ";
   return std::cerr;
}
 
inline std::ostream &Warn()
{
   std::ostream &s = Detail::gLogVerbosity < 1 ? Detail::GetNullStream() : std::cerr;
   s << "Warning in <" << Detail::gLogName << ">: ";
   return s;
}
 
inline std::ostream &Info(int minLevel)
{
   std::ostream &s = Detail::gLogVerbosity < minLevel ? Detail::GetNullStream() : std::cerr;
   s << "Info in <" << Detail::gLogName << ">: ";
   return s;
}
 
#endif