Conditional Compiling

The compiler supports conditional compiling directives in ST "Structured text" A high-level language that is block structured and syntactically resembles Pascal, IL "Instruction List" This is a low-level language and resembles assembly, FFLD "Free Form Ladder Diagram", and FBD "Function Block Diagram" A function block diagram describes a function between input variables and output variables. A function is described as a set of elementary blocks languages.

• Conditional compiling directives condition the inclusion of a part of the program in the generated code based on pragma A compiler directive communicating additional "pragmatic" information. Pragmas are processed at compile time, not at run time. They pass information to the compiler.
• Conditional compiling is an easy way to manage several various machine configurations and options in one unique application project.
• Conditional compiling uses definitions as conditions.

This is the main syntax:

#ifdef CONDITION
    statementsYES...
#else
    statementsNO...
#endif

• If CONDITION has been defined using #define syntax, then the statementsYES part is included in the code, else the statementsNO part is included.
  • The #else statement is optional.

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• Intellisense facilitates the reading by coloring in gray the part of the program which is not active.

How to define conditional compiling directives?

Language	Description
FBD Language	Directives must be entered as the text of FBD Network Breaks
FFLD Language	Directives must be entered as a network pragma with the icon. In this example image: If CONDITION has been defined using #define syntax, then The networks 2 to 4 are included in the code, else The networks 5 to 12 are included.
IL Language ST Language	Directives must be entered alone on one line of text.

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• Conditional compilation do not apply to actions in an SFC "Sequential Function Chart" It can be used to program processes that can be split into steps. The main components of SFC are: - Steps with associated actions - Transitions with associated logic conditions - Directed links between steps and transitions step.

The condition __DEBUG is automatically defined when the application is compiled in DEBUG mode.

This allows you to incorporate some additional statements (such as trace outputs) in your code that are not included in RELEASE mode.

#ifdef      __DEBUG 
     Printf('In debug mode', 0, 0, 0, 0);
#endif

See Also

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