mirror of https://github.com/davisking/dlib.git
74 lines
2.4 KiB
C++
74 lines
2.4 KiB
C++
// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
|
|
|
|
/*
|
|
|
|
This is an example showing how to control where the dlib::logger sends its messages.
|
|
This is done by creating a "hook" class that is called whenever any of the loggers want
|
|
to log a message. The hook class then outputs the messages using any method you like.
|
|
|
|
|
|
Prior to reading this example, you should understand the basics of the dlib::logger.
|
|
So you should have already read the logger_ex.cpp and logger_ex_2.cpp example programs.
|
|
|
|
*/
|
|
|
|
|
|
#include <dlib/logger.h>
|
|
|
|
using namespace dlib;
|
|
using namespace std;
|
|
|
|
class my_hook
|
|
{
|
|
public:
|
|
my_hook(
|
|
)
|
|
{
|
|
fout.open("my_log_file.txt");
|
|
}
|
|
|
|
void log (
|
|
const string& logger_name,
|
|
const log_level& ll,
|
|
const uint64 thread_id,
|
|
const char* message_to_log
|
|
)
|
|
{
|
|
// Log all messages from any logger to our log file.
|
|
fout << ll << " ["<<thread_id<<"] " << logger_name << ": " << message_to_log << endl;
|
|
|
|
// But only log messages that are of LINFO priority or higher to the console.
|
|
if (ll >= LINFO)
|
|
cout << ll << " ["<<thread_id<<"] " << logger_name << ": " << message_to_log << endl;
|
|
}
|
|
|
|
private:
|
|
ofstream fout;
|
|
};
|
|
|
|
int main()
|
|
{
|
|
my_hook hook;
|
|
// This tells all dlib loggers to send their logging events to the hook object. That
|
|
// is, any time a logger generates a message it will call hook.log() with the message
|
|
// contents. Additionally, hook.log() will also only be called from one thread at a
|
|
// time so it is safe to use this kind of hook in a multi-threaded program with many
|
|
// loggers in many threads.
|
|
set_all_logging_output_hooks(hook);
|
|
// It should also be noted that the hook object must not be destructed while the
|
|
// loggers are still in use. So it is a good idea to declare the hook object
|
|
// somewhere where it will live the entire lifetime of the program, as we do here.
|
|
|
|
|
|
logger dlog("main");
|
|
// Tell the dlog logger to emit a message for all logging events rather than its
|
|
// default behavior of only logging LERROR or above.
|
|
dlog.set_level(LALL);
|
|
|
|
// All these message go to my_log_file.txt, but only the last two go to the console.
|
|
dlog << LDEBUG << "This is a debugging message.";
|
|
dlog << LINFO << "This is an informational message.";
|
|
dlog << LERROR << "An error message!";
|
|
}
|
|
|