5. Logger registry

spdlog maintains a global (per process) registry of the created loggers.

The purpose is for loggers to be accessed easily from anywhere in the project without passing them around.

spdlog::get("logger1")->info("hello");
.. 
.. 
some other source file..
..
auto l = spdlog::get("logger1");
l->info("hello again");

If a logger is not found, an empty shared pointer is returned. You use if(l) to check the validity of the pointer l.

Registering new loggers

Normally there is no need to register loggers as they are registered automatically for you.

To register manually created loggers(i.e. not created by the spdlog.h factory functions) use the register_logger(std::shared_ptr<logger>) function:

spdlog::register_logger(some_logger);

which will register some_logger using its name.

Registry conflicts

spdlog will throw a spdlog::spdlog_ex exception on attempting to register using a name that already exists in the registry

Removing loggers from the registry

The "drop()" function can be used to remove a logger from the registry.

If no other shared_ptr pointing to the logger exists, the logger will be closed and all its resources will be freed.

spdlog::drop("logger_name");
//or remove them all
spdlog::drop_all()