1.8 KiB
Miscellaneous Stuff
Include Guard
When writing the include guard of a C/C++ header file, we require using both the modern #pragma once approach and the traditional approach based on the #ifndef, #define and #endif preprocessing directives. The file should be written like this:
#pragma once
#ifndef SOME_HEADER_H_
#define SOME_HEADER_H_
// The actual content of the header file...
#endif // SOME_HEADER_H_
The SOME_HEADER prefix is usually related to the name of the header file. It must consist of all uppercase characters, but underscores are allowed. The _H_ suffix is fixed and cannot be changed; this suffix style originates from the Linux kernel.
For example, when the header file is named wfassoc.h, the macro name would be WFASSOC_H_.
However, if the name of the header file is too simple and may collide with other header files, it would be better to prepend something to the prefix to remove this ambiguity. For example, for a project called MyRust with a header file named utils.h, a good macro name would be MY_RUST_UTILS_H_.
Block Closing Annotations
When we use preprocessor directives such as #if or #ifdef to conditionally enable or disable some code, we require you to annotate the condition after its matching #else and #endif, as shown below:
#ifdef __cplusplus
// Contents omitted...
#else // __cplusplus
// Contents omitted...
#endif // __cplusplus
Besides the preprocessor directives, you also need to write similar closing annotations for namespace (C++ only) and extern "C" blocks (C++ only), for example:
extern "C" {
// Contents omitted...
} // extern "C"
namespace foobar {
// Contents omitted...
} // namespace foobar
Note that the spaces around the // comment markers in the examples are required.