Preprocessor – the #elif Directive
This (along with the #if directive) is probably the second most complicated preprocessor directive because the controlling expression can be complex and include tricky macro replacements. #elif is one...
View ArticlePreprocessor – the #ifndef Directive
Behaviour of the #ifndef directive is the same in both C and C++. Purpose The #ifndef directive is one of five preprocessor selection statements allowing selection of alternative sections of code for...
View ArticlePreprocessor – the #else Directive
#else is one of five preprocessor selection statements allowing selection of alternative sections of code for compilation. The other four selection statements are: #ifdef, #ifndef, #if, and #elif....
View ArticlePreprocessor – the #endif Directive
Behaviour of this preprocessor directive is the same for both C and C++ compilers. Purpose The #endif directive is used end / close / terminate a selection block (#if, #ifdef, or #ifndef. Format #if...
View ArticlePreprocessor – Understanding the stringizing (#) Operator
This is one of three preprocessor operators. The other two operators are the token pasting operator (##) and the define operator. The behaviour is the same for both C and C++ compilers. Purpose The...
View ArticlePreprocessor – the #pragma Directive
Behaviour of this preprocessor directive is the same for both C and C++ compilers. Behaviour of this directive is very likely to vary from one compiler vendor to another. Purpose The #pragma directive...
View ArticlePreprocessor – the #line Directive
I don’t think I have ever seen this directive used. Behaviour of this preprocessor directive is the same for both C and C++ compilers. Purpose The #line directive allows setting the current line...
View ArticlePreprocessor – the #error Directive
Preprocessor – the #error Directive This is a very useful and often underused preprocessor directive. Behaviour of this preprocessor directive is the same for both C and C++ compilers. Purpose The...
View ArticleHow to Add Comments to Macros
Comments are an important part of documenting your code. Adding comments to macros is quite easy, but it has to be done the right way. This works with both C and C++ compilers. The easiest way to...
View ArticleKeyword – switch, case, default
The switch keyword is probably the least well understood of the C/C++ language keywords (although, const probably comes a close second). The keywords switch, case, and default always go together and...
View ArticleProgramming Error – Unintended String Concatenation
In an effort to be helpful, C and C++ compilers concatenate adjacent strings together. In the following example, the compiler will concatenate the two strings into a single string: printf("This is a...
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