--- a/STYLE.md	Mon Jan 06 12:24:43 2020 +0100
+++ b/STYLE.md	Tue Jan 07 11:01:27 2020 +0100
@@ -49,6 +49,256 @@
 
 This example will not align correctly if tabstops are not set to 8.
 
+C
+=
+
+Style
+-----
+
+- Do not exceed 80 columns.
+
+### Braces
+
+Braces follow the K&R style, they are never placed on their own lines except for
+function definitions.
+
+Do not put braces for single line statements.
+
+```c
+if (condition) {
+	apply();
+	add();
+} else
+	ok();
+
+if (condition)
+	validate();
+
+if (foo)
+	state = long + conditional + that + requires + several + lines +
+	        to + complete;
+```
+
+Functions require braces on their own lines.
+
+```c
+void
+function()
+{
+}
+```
+
+Note: the type of a function is broken into its own line.
+
+### Spaces
+
+Each reserved keyword (e.g. `if`, `for`, `while`) requires a single space before
+its argument.
+
+Normal function calls do not require it.
+
+```c
+if (foo)
+	destroy(sizeof (int));
+```
+
+### Pointers
+
+Pointers are always next variable name.
+
+```c
+void
+cleanup(struct owner *owner);
+```
+
+### Typedefs
+
+Do not use typedef for non-opaque objects. It is allowed for function pointers.
+
+```c
+struct pack {
+	int x;
+	int y;
+};
+
+typedef void (*logger)(const char *line);
+```
+
+Note: do never add `_t` suffix to typedef's.
+
+### Naming
+
+- English names,
+- No hungarian notation,
+
+Almost everything is in `underscore_case` except macros and enumeration
+constants.
+
+```c
+#if defined(FOO)
+#	include <foo.hpp>
+#endif
+
+#define MAJOR 1
+#define MINOR 0
+#define PATCH 0
+
+enum color {
+	COLOR_RED,
+	COLOR_GREEN,
+	COLOR_BLUE
+};
+
+void
+add_widget(const struct widget *widget_to_add);
+```
+
+### Header guards
+
+Do not use `#pragma once`.
+
+Header guards are usually named `PROJECT_COMPONENT_FILENAME_H`.
+
+```c
+#ifndef FOO_COMMON_UTIL_H
+#define FOO_COMMON_UTIL_H
+
+#endif /* !FOO_COMMON_UTIL_HPP */
+```
+
+### Enums
+
+Enumerations constants are always defined in separate line to allow commenting
+them as doxygen.
+
+Note: enumeration constants are prefixed with its name.
+
+```c
+enum color {
+	COLOR_RED,
+	COLOR_GREEN,
+	COLOR_BLUE
+};
+```
+
+### Switch
+
+In a switch case statement, you **must** not declare variables and not indent
+cases.
+
+```c
+switch (variable) {
+case foo:
+	do_some_stuff();
+	break;
+default:
+	break;
+}
+```
+
+### Files
+
+- Use `.c` and `.h` as file extensions,
+- Filenames are all lowercase.
+
+### Comments
+
+Avoid useless comments in source files. Comment complex things or why it is done
+like this. However any public function in the .h **must** be documented as
+doxygen without exception.
+
+```c
+/*
+ * Multi line comments look like
+ * this.
+ */
+
+// Short comment
+```
+
+Use `#if 0` to comment blocks of code.
+
+```c
+#if 0
+	broken_stuff();
+#endif
+```
+
+### Includes
+
+The includes should always come in the following order.
+
+1. System headers (POSIX mostly)
+2. C header
+3. Third party libraries
+4. Application headers in ""
+
+```c
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <string.h>
+
+#include <libircclient.h>
+
+#include "foo.h"
+```
+
+Programming
+-----------
+
+### C Standard
+
+Use C99 standard without extensions.
+
+### Assertions
+
+Use the `assert` macro from the assert.h header file to verify programming
+errors.
+
+For example, you may use `assert` to verify that the developer access the data
+between the bounds of an array:
+
+```c
+int
+get(struct data *data, unsigned index)
+{
+	assert(index < data->length);
+
+	return data->buffer[index];
+}
+```
+
+The `assert` macro is not meant to check that a function succeeded, this code
+must not be written that way:
+
+```c
+assert(listen(10));
+```
+
+### Return
+
+The preferred style is to return early in case of errors. That makes the code
+more linear and not highly indented.
+
+This code is preferred:
+
+```c
+if (a_condition_is_not_valid)
+	return false;
+if (an_other_condition)
+	return false;
+
+start();
+save();
+
+return true;
+```
+
+Additional rules:
+
+- Do never put parentheses between the returned value,
+- Do not put a else branch after a return.
+
 C++
 ===