Changes between Initial Version and Version 1 of Logging

Timestamp:

2012-08-15T12:25:27Z (12 years ago)

Author:

Vojtech Horky

Comment:

First version

Logging

@@ +1 @@
+= Logging functions in HelenOS =
+
+If you want to add logging to your application, you can use already existing functions in `libc`. Currently, the implementation is trivial as the messages are only printed to the screen but using single API allows for further improvements (logging to file/over network etc.).
+
+To use logging functions, include `io/log.h` and initialize the logging subsystem. After that, you can use the `log_msg` to do the logging.
+
+{{{
+#!c
+...
+#include <io/log.h>
+
+#define NAME "myapp"
+...
+
+int main(int argc, char *argv[])
+{
+    log_init(NAME, LVL_NOTE);
+    ...
+    if (rc != EOK) {
+        log_msg(LVL_ERROR, "Something failed (rc=%d), trying fallback...", rc);
+        ...
+    }
+}
+}}}
+
+The first argument to `log_init` is application name, the second is the default logging level. Messages with higher level won't be printed at all.
+
+`log_msg` is a `printf`-like function where first argument is level of the message (its seriousness).
+
+Currently, following levels are recognised.
+
+||= Name =||= Typical usage =||
+|| `LVL_FATAL` || Fatal error, program is not able to recover at all. ||
+|| `LVL_ERROR` || Serious error but the program can recover from it.[[BR]]E.g. driver cannot control one device but otherwise is healthy. ||
+|| `LVL_WARN` || Easily recoverable problem, such as one corrupted packet that can be skipped. ||
+|| `LVL_NOTE` || Notice of higher importance to the user, such as discovery of a new device. ||
+|| `LVL_DEBUG` || Debugging-purpose message. ||
+|| `LVL_DEBUG2` || More detailed debugging message. ||
+