C Coding Standard

Language consideration

• Avoid using assignment inside an expression.
• Never use goto.
• Never use return if this is not the last instruction of a routine.
• Use break only to separate branches of a switch statement.
• A declaration

  extern void foo();

  needs to be

  extern void foo(void);

  Otherwise it is not considered a prototype (for compatability with K&R) (see bug#13870).

• Use "%f" instead of "%lf" specifier in printf and family to print double (see bug#13872). This does not affect scanf and family.

Style

• Always use curly braces, even when there is only one instruction. Instead of

if (a) do_something();

write

if (a) {
	do_something();
}

• Place opening brace at the same line as the condition as in

while (expr) {
	...
}
for (;;) {
	...
}

unless the expression is very long as in

if
	(very_long_expression)
{
	...
}

• Surround else with braces as in

if (expr) {
	...
} else {
	...
}