Delphi - How to use more defined values in conditional compilation

Can I combine some IFDEFS in my source?

For example:

{$IFDEF INCOMING or OUTGOING开发者_如何学Python}
...
{$ENDIF}

Thanks for your help: dd

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Use $IF with Defined() rather than $IFDEF:

{$IF Defined(INCOMING) or Defined(OUTGOING)}
...
{$IFEND}

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Alternative, for older versions:

{$IFDEF INCOMING}
  {$DEFINE INCOMING_OR_OUTGOING}
{$ENDIF}
{$IFDEF OUTGOING}
  {$DEFINE INCOMING_OR_OUTGOING}
{$ENDIF}

{$IFDEF INCOMING_OR_OUTGOING}
...
{$ENDIF}

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I don't believe the $IFDEF supports it, but the $IF does. http://docs.embarcadero.com/products/rad_studio/delphiAndcpp2009/HelpUpdate2/EN/html/devcommon/compdirsifdirective_xml.html

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Here's a variation of David's answer using 'not'.

I use this when I want to disable the splash screen on my apps while in debug mode. It prevents me from accidentally leaving the splash disabled if I forget to undefine NOSPLASH in the release build.

  {$IF not (Defined(NOSPLASH) AND Defined(DEBUG))}
     //code to create splash 
  {$IFEND}