Code Style C
This is just a brief overview of the C Code Style used for our projects. The EDK II Project requires the use of https://github.com/uncrustify/uncrustify to automatically format C code to match the EDK II C Coding Standard. Details on how to install and run uncrustify for EDK II can be found at EDK II Code Formatting.
The official C Coding Standards specification can be found at:
Overview
- CamelCase used for variables, functions and file names
- UPPERCASE used for types and macros
- Use UEFI types rather than C types
- int=>INTN; unsigned int=>UINTN; void=>VOID; etc...
- Limit line length to 80 characters
- 2 spaces of indentation
- Never use tab characters.
- Set editor to insert spaces rather than a tab character.
- if, for, while, etc. always use { }, even when there is only one
statement
- The opening brace ({) should always appear at the end of the line previous line.
- The opening brace ({) for a function should always appear separately on the a new line.
Example of Properly Formatted Code
C File Example:
#include "FooFileName.h"
/**
Brief and Detailed Descriptions.
@param[in] Arg1 Description of Arg1.
@param[in] Arg2 Description of Arg2, which is optional.
@param[out] Arg3 Description of Arg3.
@param[in, out] Arg4 Description of Arg4.
@retval EFI_SUCCESS Description of what EFI_SUCCESS means.
@retval !EFI_SUCCESS Failure.
**/
EFI_STATUS
EFIAPI
FooName (
IN UINTN Arg1,
IN UINTN Arg2 OPTIONAL,
OUT UINTN *Arg3,
IN OUT UINTN *Arg4
)
{
UINTN Local;
UINTN AnotherLocal;
...
for (Local = 0; Local < 5; Local++) {
if (Local == 2) {
Print (L"Local: %d (yes! 2)\n", Local);
} else {
Print (L"Local: %d\n", Local);
}
}
...
}
H File Example:
#ifndef _FOO_FILE_NAME_H_
#define _FOO_FILE_NAME_H_
#define FOO_MACRO(a, b) ((a) * (b))
#define FOO_CONSTANT 0xcafe
/**
Brief and Detailed Descriptions.
@param[in] Arg1 Description of Arg1.
@param[in] Arg2 Description of Arg2, which is optional.
@param[out] Arg3 Description of Arg3.
@param[in, out] Arg4 Description of Arg4.
@retval EFI_SUCCESS Description of what EFI_SUCCESS means.
@retval !EFI_SUCCESS Failure.
**/
EFI_STATUS
EFIAPI
FooName (
IN UINTN Arg1,
IN UINTN Arg2 OPTIONAL,
OUT UINTN *Arg3,
IN OUT UINTN *Arg4
);
...
#endif
Examples
CamelCase
Used for variables, functions and file names
Correct:
#include "FooFileName.h"
...
VOID SuperFunction (
...
UINTN ALocalVariable;
UINTN UefiVersion;
Incorrect:
#include "foo-file_name.h"
...
VOID superFunction (
...
UINTN a_local_variable;
UINTN UEFIVersion;
UPPERCASE
Used for types and macros
Correct:
#define FOO_MACRO(a, b) ((a) * (b))
typedef struct _STRUCT_NAME STRUCT_NAME;
struct _STRUCT_NAME {
...
};
Incorrect:
#define FooMacro(a, b) ((a) * (b))
#define Foo_Macro(a, b) ((a) * (b))
typedef struct _Struct_Name StructName;
Use UEFI types
Don't use C types directly
Correct:
INTN ALocalVariable;
UINTN UefiVersion;
VOID *Ptr;
Incorrect:
int ALocalVariable;
unsigned int UefiVersion;
void *Ptr;
2 spaces of indentation
Correct:
if (TRUE) {
Print (L"Hello, world!\n");
}
Incorrect:
if (TRUE) {
Print (L"Hello, world!\n");
}
Always use
If, for, while, etc. always use { }, even when there is only one statement
Correct:
if (TRUE) {
Print (L"Hello, world!\n");
}
Incorrect:
if (TRUE)
Print (L"Hello, world!\n");