Scope

This guide applies to all .c and .h files. If there is a conflict between local style and this guide, this guide wins.

1) Indentation and whitespace

if (cond) {
    do_work();
}

a = b + c;
mask = (x << 2) | y;
ptr = base + offset;

i++;
--j;
p = &obj;
q = *p;

if (a == b)             /* not: if ( a == b ) */
func(x, y);             /* not: func( x, y ) */

2) Braces and block layout

static int foo(int x)
{
    if (x > 0) {
        return x;
    }

    return 0;
}

if (ok) {
    do_a();
} else {
    do_b();
}

3) do { } while (); formatting

• Attach the while (...) to the closing brace line.

Example:

do {
    work();
} while (cond);

4) Pointer alignment

• The * binds to the name, not the type.

Examples:

char *p;
const struct Foo *foo;
struct Node *node;
void (*fn)(int x);

• For multiple declarators, keep the * with each name.

Example:

char *a, *b;

5) Line length

• Maximum line length is 120 columns.
• Wrap long expressions, conditions, and function calls.

if (really_long_condition &&
    another_condition &&
    final_condition) {
    ...
}

rc = some_function(arg1, arg2, arg3,
                   arg4, arg5);

bug("%s: dev=%u ep=%u state=%lu\n",
            __func__, dev, ep, state);

6) Line endings

• Files must use Unix LF line endings.
• Avoid committing CRLF.

7) Statements and blank lines

• One statement per line.
• Use blank lines to separate logical sections within a function.
• Avoid trailing whitespace.
• Prefer braces for control blocks to reduce diff-risk.

Preferred:

if (error) {
    return FAIL;
}

8) Headers and includes

• Group includes:
  1. Local header for the .c file (if applicable)
  2. System/SDK headers
  3. Project headers
• Separate include groups with a blank line.
• Prefer forward declarations in headers where possible to reduce include coupling.

9) Formatting workflow

• Format files consistently before submitting changes.
• Avoid mixing large reformat-only diffs with functional changes unless necessary.