How to: Use the #localmacro and #globalmacro Directives

Artikel
2015-05-18

Applies To: Microsoft Dynamics AX 2012 R3, Microsoft Dynamics AX 2012 R2, Microsoft Dynamics AX 2012 Feature Pack, Microsoft Dynamics AX 2012

The #localmacro directive is a good choice when you want a macro to have a value that is several lines long, or when your macro value contains a closing parenthesis. The #localmacro directive is a good choice when you want your macro value to be lines of X++ or SQL code.

Note

The #localmacro directive can be written as #macro. However, #localmacro is the recommended term. Both macros have the same behavior.

Prerequisites

For this topic, you must understand the information in How to: Use Parameters with Macros.

Using #localmacro

The following code sample shows how to use the #localmacro directive. It demonstrates that the #undef directive does not affect #localmacro macros. It also shows that #if tests cannot determine whether a #localmacro macro has been defined.

    static void LocalMacroJob(Args _args)
    {
        ;
        #localmacro.LMacReportLog
            print("%1  --LM, print.");
            info("%1  --LM, Infolog.");
        #endmacro
    
        #LMacReportLog(g11: Hello World )
    
        #if.LMacReportLog
            info("The # IF LMacReportLog is true");
        #endif
    
        #undef.LMacReportLog
    
        #LMacReportLog(g22: Greetings World)
    
        #localmacro.LMacReportLog
        #endmacro // No lines for value before this end.
    
        #LMacReportLog(g33: Bye Bye) // Not present in the output.
        pause;
    
    /*************  Actual Infolog output
    Message (03:10:17 pm)
    g11: Hello World   --LM, Infolog.
    g22: Greetings World  --LM, Infolog.
    *************/
    }

Differences Between #define and #localmacro

There are differences between #define and #localmacro.

Termination Syntax

The main difference between a #define macro and a #localmacro macro is in how their syntax is terminated. The terminators are as follows:

#define – is terminated by– )
#localmacro – is terminated by– #endmacro

#localmacro is a better choice for macros with multiple line values. Multiple line values are typically lines of X++ or SQL code. X++ and SQL contain lots of parentheses, and these would prematurely terminate a #define.

Both #define and #localmacro can be declared and terminated on either a single line or on subsequent lines. In practice, the #define is terminated on the same line that it is declared on. In practice, the #localmacro is terminated on a subsequent line.

#if and #undef Do Not Apply to #localmacro

By using the #if directive, you can test whether a macro name is declared with the #define directive. However, you cannot test whether the macro name is declared with the #localmacro directive.

Only macros declared by using the #define directive are affected by the #undef directive.

Redefining a #localmacro By Using #define

In a #define directive, you can specify a name that is already in scope as a #localmacro. The effect is to discard the #localmacro and create a #define macro.

This also applies to the opposite sequence, which means that a #localmacro can redefine a #define.

Avoid Using #globalmacro

A #localmacro (that has both a macro name and a value) always overrides a previous #localmacro that has the same name. However, you cannot always be sure whether the override occurs when you use #globalmacro. For this reason we recommend that you do not use #globalmacro.

This same problem occurs with #globaldefine.

Code Sample Comparing #globalmacro and #localmacro

The following X++ code sample shows that #localmacro overrides a #globalmacro of the same macro name, but that #globalmacro does not override #localmacro.

    static void GlobalMacroNotOverrideJob(Args _args)
    {
        ;
        //---------  LGMa ,  L then G  ---------
    
        #localmacro.LGMa
            info("LGMa: Loc 11");
        #endmacro
    
        #globalmacro.LGMa
            info("LGMa: Glob 12");
        #endmacro
    
        #LGMa
    
        //---------  LGMb ,  G then L  ---------
    
        #globalmacro.LGMb
            info("LGMb: Glob 24");
        #endmacro
    
        #localmacro.LGMb
            info("LGMb: Loc 25");
        #endmacro
    
        #LGMb
    
    /****************  Actual Infolog output
    Message (06:39:42 am)
    LGMa: Loc 11
    LGMb: Loc 25
    ****************/
    }

No Special Precedence Between Macro and Define Directives

Where both macro names and values are supplied, the #globalmacro directive cannot override the #define directive. Also, the #globaldefine directive cannot override the #localmacro directive.

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