Beeper

A simple C logging library featuring

• multiple, completely independent instances,
• multiple output streams, either for narrow or wide characters and with the option to disable the formatting, and
• customizable output styles, allowing users to choose which elements to include in the log messages, adjust text color and attributes, and define a callback function to be called whenever a log message is sent.

This project is the successor to my bad, purely macro-based logging.

Building it

• Ensure you have
  • a working C compiler
  • CMake
  • a build system
• Create a "build" directory in the repository root and cd into it
• Run cmake
• Build the library using your build system

Including it

• Add build/libbeeper.a to your project source
• Include build/beeper.h in your source code

Using it

Instances

Although it supports multiple instances, Beeper is primarily designed for single-instance applications. For this reason, instead of explicitly providing an instance alongside each operation, users define a global active beeper to receive all requests.

Start by creating a beeper, providing a short identifier to indicate what the instance represents:

bp_beeper beeper = bp_beeper_new(/* identifier: */ "id");

If you're only going to use a single instance, you can discard the return value of this function – it's only used to switch between instances.

Newly created beepers are automatically selected as active beeper. You can select a different instance like this:

bp_beeper_select(/* handle: */ beeper);

Once you're done logging, destroy the active beeper to release the memory it occupied:

bp_destroy();

Recipients

Before we can start logging, we need to add some recipients to our beeper. Recipients consist of a FILE* alongside some options.

Let's add stdout as a recipient:

bp_recipient_add(/* stream: */ stdout, /* wide: */ false, /* formatted: */ true);

If you need to remove a recipient, you can do so as follows:

bp_recipient_remove(/* stream: */ stdout);

Recipients are cleaned up as part of bp_destroy(), so there's no need to remove them manually.

Logging

Now we can start logging messages. For example, we can log a warning as follows:

beep(/* style: */ warn, "Problematic integer: %d", 45)

The beep macro accepts a message style (see Styles), followed by a (literal!) format string and the values to go alongside it (Beeper wraps around the printf family of functions).

For more control, there are also the beep_with (to explicitly select an instance for this specific message), beep_at (to supply a custom origin file and line), and beep_with_at (both) macros.

The header also declares some macros useful for quick debugging. For example, you can quickly log the value of an integer as follows:

int integer = 46;
beep_i(integer);

Refer to the header to find the other types you can log in this manner.

Styles

Beeper offers the following built-in message styles: success, info, warn, fail, and debug.

However, we can also add our own or overwrite the existing ones:

bp_style_set(/* name: */ "custom", /* style: */ (bp_style){
  .foreground_color = BP_COLOR_DARK_PURPLE,
  .italic = true,
  .show_style = true,
  .hide_origin = true
});

Refer to the header to discover all the stylization options.

This style produces the following output:

To unset a style, use the following function:

bp_style_unset(/* name: */ "custom");

If your style overwrote a built-in style, unsetting it restores the built-in one. Also, like the recipients, custom styles are cleaned up as part of bp_destroy(), so it's not required to manually unset them.