wang-bin / ezlog

a tiny and easy to use log system for c/c++

A tiny and flexible log library for C/C++. Written in C.

Platform tested: linux, win32, wince, mac

Usage:

####0. #include "ezlog.h" then Initialize ezlog. e.g.

ezlog_init_default();

This will display the message to console, and use the format "YY%-%MM%-%DD% %hh%:%mm%:%ss% {tid:%tid% pid:%pid}[%file%] %func% @%line%: %msg".

If you don't want to log to console, you can call ezlog_set_default_appender(0) after ezlog_init_default(), or just don't call ezlog_init_default() at all.

If you need to log to a file

ezlog_register_appender(file_appender("ezlog.txt", Append));

If you want to use other target, you can define your own appender.

typede (*appender)(consttruct {
    void (*handle)(const char* msg, void* opaque);
    void (*close)(void* opaque);
    void *opaque;
} appender_t;

e.g.

appender_t.handle is

void widget_appender_handle(const char* msg, void *opaque) {
    ((Widget*)opaque)->showText(msg);
}

appender_t.opaque is your widget instance

and for android

void android_appender_handle(const char* msg, void *) {
    __android_log_print(ANDROID_LOG_DEBUG, "%s", msg); //TODO: logtag
}

####1. Setup log message format (aka layout). ezlog supports global layout and appender specified layout.
If you use ezlog_init_default() before and wanna keep the defaul
format, skip this step. Log message will use the last format you defined.

Key words: YY, MM, DD, hh, mm, ss, ms, tid, pid, file, func, line, msg.
It's easy to understand what they mean, so I will not explain these. A key word must between two "%",
except the first and the last. If string between "%" is not a key word, ezlog will print it with out any change.
If use key word func, the complete function name including return type, class, parameters will be supported
if compiled with gcc.

set the global layout:

ezlog_set_global_layout("MM%-%DD% %hh%:%mm%:%ss% [tid:%tid%]-[%file%] %func% @%line%: %msg");

or the deprecated one

ezlog_init_layout("MM%-%DD% %hh%:%mm%:%ss% [tid:%tid%]-[%file%] %func% @%line%: %msg");

If you use ezlog_init_default(), skip this step.

Set an appender's layout:

void ezlog_set_appender_with_layout(appender handle, const char* format);

This function will add the appender if not exists.

####2. Start your logging. You can add additional messages. It supports printf like format. If nothing
else you want to put, just keep the parameter empty.

ezlog_debug("Hello, cruel world!");  
ezlog_warn("Damn! %s", __DATE__);  
ezlog_debug();                            //Only display the formated keywords message you defined  

####3. Clean up. If you use the gcc/clang toolchain (VC not supported yet), it will be called after main() auto.

ezlog_fini();

Qt Wrapper

Qt's logging functions such as qDebug(), qWarning() are designed customizable with your own message handler. This wrapper use ezlog as the handler.
It's very easy to use. just #include "qtezlog.h", and call

ezlog::QtEZLog::install();

Then qDebug(), qWarning() will be formated with ezlog's default layout.
TO restore the Qt's default, call

ezlog::QtEZLog::uninstall();

To use a new layout, call

ezlog::QtEZLog::setLayout(const QString& fmt);

[email protected]
20120224
Last updated: 20121202

ezlog's Issues

lock scope

now is global, can we use a smaller scope? mutex in struct? set null mutex in ezlog ?

vc6 support

it seems that vc6 does not support va args macro.

use logging thread

do not affect the original thread

loop log task queue in a thread

enable ezlog without code change

add macro in makefiles and link to ezlog++

global layout may not work for file appender

tst_ezlog/main.c

user defineded lock

like ffmpeg lockmgr. null means no lock, then user can use scoped lock outside instread of global lock.

remove ezmutex?

console color

e.g. red for error, white for debug

BOOL SetConsoleTextAttribute( HANDLE hConsoleOutput,WORD wAttributes);

http://blog.csdn.net/morewindows/article/details/6789206

vc not support empty macro parameter

define ezlog_debug(fmt, ...)

environment variables

EZLOG_FILE
EZLOG_LAYOUT

qtwrapper must use macro

otherwise the function name, line, file are wrong

c++ macro to replace existing log system

define qDebug(...) ezlog_qt(FILE, ....).print()
what about qDebug() << xxx
class ezlog_qt {

}
operator <<

android need additional parameters in ctor
define android_log(...) ezlog_android(TAG, LEVEL, __FILE,....)
class ezlog_android {

}

appender struct instead of function ptr

typdef struct append {
void *opaq;
append_func callback;
}

it will be more flexible

api: set_layout_for_appender