uLog

#include "ulog.h"

// To use uLog, you must define a function to process logging messages. It can
// write the messages to a console, to a file, to an in-memory buffer: the
// choice is yours.  And you get to choose the format of the message.  
//
// The following example prints to the console.  
//
// One caveat: msg is a static string and will be over-written at the next call
// to ULOG.  This means you may print it or copy it, but saving a pointer to it
// will lead to confusion and astonishment.
//
void my_console_logger(ulog_severity_t severity, const char *msg) {
     printf("%s [%s]: %s\n",
         get_timestamp(),    // user defined function
         ulog_severity_name(severity),
         msg);
}

int main() {
    int arg = 42;

    ULOG_INIT();

    // log messages with a severity of WARNING or higher to the console.  The
    // user must supply a method for my_console_logger, e.g. along the lines
    // of what is shown above.
    ULOG_SUBSCRIBE(my_console_logger, ULOG_WARNING_LEVEL);

    // log messages with a severity of DEBUG or higher to a file.  The user must
    // provide a method for my_file_logger (not shown here).
    ULOG_SUBSCRIBE(my_file_logger, ULOG_DEBUG_LEVEL);

    ULOG_INFO("Info, arg=%d", arg);        // logs to file but not console
    ULOG_CRITICAL("Critical, arg=%d", arg);  // logs to file and console

    // dynamically change the threshold for a specific logger
    ULOG_SUBSCRIBE(my_console_logger, ULOG_INFO_LEVEL);

    ULOG_INFO("Info, arg=%d", arg);          // logs to file and console

    // remove a logger
    ULOG_UNSUBSCRIBE(my_file_logger);

    ULOG_INFO("Info, arg=%d", arg);          // logs to console only
}