global compiler directives

Free Pascal supports compiler directives in the source file. Basically the same directives as in Turbo Pascal, Delphi and Apple Pascal (Mac OS) pascal compilers are supported. Some are recognized for compatibility only, and have no effect.

Syntax

General:

• {$mode} selects the compiler mode
• {$modeSwitch} turns on or off specific mode features

Specific:

• {$extendedSyntax} enables multiple syntax extensions
• {$pointerMath} automatically defines operators for new pointer data types (since FPC 2.6.0)
• {$openStrings} or {$P} determines, whether all routine parameters of type string are considered to be open string parameters; this parameter only has effect for short strings, not for ANSIStrings.
• {$varPropSetter}

Code generation

• {$codePage} determines which code page is used by the program
• {$E} emulate co-processor
• {$extension} determines file name suffix of the generated executable
• {$libPrefix} determines file name prefix a generated library
• {$libSuffix} determines file name suffix a generated library
• {$memory} determines size of memory to use
• {$PascalMainName} determines name of entry point
• {$PIC} enables position independent code code generation
• {$smartlink} determines smartlinking
• {$sysCalls} determines system call calling conventions on Amiga/MorphOS

Data inclusion

• {$debugInfo} or {$D} inserts GNU debugging information into generated code
• {$referenceInfo} or {$Y} creates Delphi-compatible browser information (not yet fully supported)

Paths

• {$frameworkPath} (on Darwin)
• {$includePath} determines path for include files
• {$libraryPath} determines the path to library files
• {$objectPath} defines the path to search for object files at
• {$unitPath} determines search path for units

Target-dependent

Novell NetWare only

• {$copyright} inserts copyright information
• {$screenName} determines screen name of application
• {$threadName} defines name of thread

Palm OS and Garnet OS only

• {$appID} defines four-character application identifier
• {$appName} determines the name of the application

Windows-based systems

• {$imageBase} specifies DLL image base location
• {$minStackSize}
• {$maxStackSize}
• {$setPEFlags}
• {$version} defines version number of a DLL

Miscellaneous

• {$appType} determines the program type

Compile-time data

• {$profile} enables generation of profile code

Ignored

• {$description}: introduced for compatibility and as of FPC 3.0.4 ignored
• {$G} would generate 80286 code with TP
• {$localSymbols} or {$L}
• {$N} (numeric processing)
• {$O} enabled level 2 optimizations. It is not recognized anymore since FPC 2.0.0. Use {$optimization} instead.
• {$weakPackageUnit}

See also

• Pascal basics
• § “global directives” in the Free Pascal programmer’s guide

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From the Free Pascal wiki, page "global compiler directives", as it stood on 2021-02-19 after a change by Kai Burghardt, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.