• Indentation in tabs, 8 characters wide, spaces after the tabs where vertical alignment is required (see below)

Note: this file uses spaces due to markdown rendering issues for tabs. Code must be implemented using tabs.

• Max line width 80ch, do not break up printed strings though

• Break up long lines at logical groupings, one line for each logical group

int a = somelongname() +
        someotherlongname();

if (a < 0 &&
    (b > 20 & d < 10) &&
    d != 0.0)


somelongfunctioncall(arg1,
                     arg2,
                     arg3);

• Function declarations: return type on separate line, {} on separate line, arguments broken up as above.

static inline int
foobar(int a, int b)
{

}

void
somenamethatiswaytoolong(int a,
                         int b,
                         int c)
{
}

• /* comments only */, no // comments

• variable_name, not VariableName or variableName. same for functions.

• no typedefs of structs, enums, unions

• if it generates a compiler warning, it needs to be fixed

• if it generates a static checker warning, it needs to be fixed or commented

• declare variables at the top, try to keep them as local as possible. Exception: if the same variable is re-used in multiple blocks, declare it at the top. Exception: basic loop variables, e.g. for (int i = 0; ...)

int a;
int c;

if (foo) {
        int b;

        c = get_value();
        usevalue(c);
}

if (bar) {
        c = get_value();
        useit(c);
}

• do not mix function invocations and variable definitions.

wrong:

{
        int a = foo();
        int b = 7;
}

right:

{
        int a;
        int b = 7;

        a = foo();
}

There are exceptions here, e.g. tp_libinput_context(), litest_current_device()

• if/else: { on the same line, no curly braces if both blocks are a single statement. If either if or else block are multiple statements, both must have curly braces.

if (foo) {
        blah();
        bar();
} else {
        a = 10;
}

• public functions MUST be doxygen-commented, use doxygen's @foo rather than \foo notation

• #include "config.h" comes first, followed by system headers, followed by external library headers, followed by internal headers. sort alphabetically where it makes sense (specifically system headers)

#include "config.h"

#include <stdio.h>
#include <string.h>

#include <libevdev/libevdev.h>

#include "libinput-private.h"

• goto jumps only to the end of the function, and only for good reasons (usually cleanup). goto never jumps backwards

• Use stdbool.h's bool for booleans within the library (instead of int). Exception: the public API uses int, not bool.