A compiler directive, also called as a pre-processor directive, is an instruction to the compiler to perform or complete a specific programming task during compilation. While in the preprocessor step, the compiler looks for a compiler directive and then processes the tasks when encountered. After performing the tasks, the compiler checks for any syntax errors. It then converts the source into an object code. Compiler directives are an integral part of every programming language and are used by every programmer, be it software developer or adult web developer.
In assembly languages such as C and C, #define and #include are called as preprocessor directives. The # or the pound symbol is the first character of a line. It indicates that the next word (which is ‘include’) is the directive that is to be evaluated. Let us learn a bit more about these two compiler directives:
include: the item that follows includes (compiler directive) is the name of the file. The file is often referred to as “header files” (.h files) because the ‘include’ directive is inserted at the head as one of the first items. Example: #include
define: an identifier name and value follow the define directive. The compiler stores this identifier name and value and when it confronts the identifier name in the block of code, it then substitutes the value in place of the identifier name. Example #define PI 3.14159
Compiler directives are also used in other high-level languages. In Ada programming language compiler directives are called ‘Pragmas’ whereas in Turbo Pascal the directives are known as significant comments. Perl, an important programming language used by most adult web developers, employs the word “use” as a compiler directive.
Compiler directives are also a part of the Visual Basic language. Microsoft first introduced compiler directives in VB.NET. Adult website developers well-versed with this programming language know how to use the compiler directive effectively. This sound knowledge of programming makes active adult developers an expert in devising user-friendly websites.