| Free Pascal | |
|---|---|
 Free Pascal 3.2.2 help screen | |
| Developers | Florian Klämpfl &volunteers |
| Initial release | 1997; 29 years ago (1997) |
| Stable release | 3.2.2 / May 20, 2021; 4 years ago (2021-05-20) |
| Preview release | 3.3.1 |
| Written in | Object Pascal |
| Operating system | Cross-platform,embedded |
| Type | Compiler,embedded operating system |
| License | GNU General Public License for compiler and utility executables.GNU Lesser General Public License with static linking exception for runtime, package, component and other libraries that become part of executables created with compiler |
| Website | freepascal |
| Repository | |
Free Pascal Compiler (FPC) is acompiler for the closely related programming-language dialectsPascal andObject Pascal. It isfree software released under theGNU General Public License, withexception clauses that allow static linking against its runtime libraries and packages for any purpose in combination with any other software license.
It supports its own Object Pascal dialect, as well as the dialects of several other Pascal family compilers to a certain extent, including those ofBorland Pascal (named "Turbo Pascal" until the 1990 version 6), Borland (later Embarcadero)Delphi, and some historicalMacintosh compilers. The dialect is selected on aper-unit (module) basis, and more than one dialect can be used per program.
It follows awrite once, compile anywhere philosophy and is available for manyCPU architectures andoperating systems (seeTargets). It supports inlineassembly language and includes an internal assembler capable of parsing several dialects such as AT&T and Intel style.
There are separate projects to facilitate developingcross-platformgraphical user interface (GUI) applications, the most prominent one being theLazarusintegrated development environment (IDE).
Initially, Free Pascal adopted thede facto standard dialect of Pascal programmers, Borland Pascal, but later adopted Delphi's Object Pascal. From version 2.0 on, Delphi compatibility has been continuously implemented or improved.
The project has acompilation mode concept,[clarification needed] and the developers made it clear that they would incorporate working patches for the standardized dialects of theAmerican National Standards Institute (ANSI) andInternational Organization for Standardization (ISO) to create a standards-compliant mode.
A small effort has been made to support some of theApple Pascal syntax to ease interfacing to theClassic Mac OS andmacOS. The Apple dialect implements some standard Pascal features that Turbo Pascal and Delphi omit.
The 2.2.x release series did not significantly change the dialect objectives beyond roughly Delphi 7 level syntax, instead aiming for closer compatibility. A notable exception to this was the addition of support forgenerics to Free Pascal in version 2.2.0, several years before they were supported in any capacity by Delphi.
In 2011 several Delphi 2006-specific features were added in the development branch, and some of the starting work for the features new in Delphi 2009 (most notably the addition of theUnicodeString type) was completed. The development branch also has anObjective-Pascal extension forObjective-C (Cocoa) interfacing.
Beginning with version 2.7.1, Free Pascal added support for ISO Pascal. As of version 3.0.0, it has been able to compile standardpascal.org's P5 ISO Pascal compiler with no changes.
Free Pascal was created when Borland clarified that Borland Pascal development forMS-DOS would stop with version 7. Student Florian Paul Klämpfl began developing his own compiler written in the Turbo Pascal dialect which produced32-bit code for the GO32v1DOS extender, (developed and used by theDJ's GNU Programming Platform project).
Originally, the compiler was a 16-bit executable compiled byTurbo Pascal. After two years, the compiler was able tocompile itself into a 32-bit executable.
The initial 32-bit compiler was published on theInternet, and the first contributors joined the project. Later, aLinux port was created by Michael van Canneyt, five years before theBorland Kylix Pascal compiler for Linux became available.
The DOS port was adapted for use inOS/2 using theEberhard Mattes eXtender (EMX) which made OS/2 the second supported compiling target. As well as Florian Klämpfl the original author, Daniël Mantione also contributed significantly to make this happen, providing the original port of the run-time library to OS/2 and EMX. The compiler improved gradually, and the DOS version migrated to the GO32v2 extender. This culminated in release 0.99.5, which was much more widely used than prior versions, and was the last release aiming only for Borland Pascal compliance; later releases added a Delphi compatibility mode. This release was also ported to systems usingMotorola 68000 family (m68k) processors.
With release 0.99.8 theWin32 target was added, and a start was made with incorporating some Delphi features. Stabilizing for a non-beta release began, and version 1.0 was released in July 2000. The 1.0.x series was widely used, in business and education. For the 1.0.x releases, the port to 68k CPU was redone, and the compiler produced stable code for several 68kUnix-like andAmigaOS operating systems.
During the stabilization of what would become 1.0.x, and also when porting to theMotorola 68k systems, it was clear that the design of the code generator was far too limited in many aspects. The principal problems were that adding processors meant rewriting the code generator, and that the register allocation was based on the principle of always keeping three free registers between building blocks, which was inflexible and difficult to maintain.
For these reasons, the 1.1.x seriesbranched off from the 1.0.x main branch in December 1999. At first, changes were mostly clean-ups and rewrite-redesigns to all parts of the compiler. The code generator and register allocator were also rewritten. Any remaining missing Delphi compatibility was added.
The work on 1.1.x continued slowly but steadily. In late 2003, a workingPowerPC port became available, followed by anARM port in summer 2004, aSPARC port in fall 2004, and anx86-64-AMD64 port in early 2004, which made the compiler available for a 64-bit platform.
In November 2003, a firstbeta release of the 1.1.x branch was packaged and numbered 1.9.0. These were quickly followed by versions 1.9.2 and 1.9.4; the latter introduced OS X support. The work continued with version 1.9.6 (January 2005), 1.9.8 (late February 2005), 2.0.0 (May 2005), 2.0.2 (December 2005), and 2.0.4 (August 2006).
In 2006, some of the major reworks planned for 2.2, such as the rewrite of the unit system, had still not begun, and it was decided to instead start stabilizing the already implemented features.
Some of the motives for thisroadmap change were the needs of the Lazarus integrated development environment project, particularly the internal linker, support forWin64,Windows CE, and OS X onx86, and related features likeDWARF. After betas 2.1.2 and 2.1.4, version 2.2.0 was released in September 2007, followed by version 2.2.2 in August 2008 and version 2.2.4 in March 2009.
The 2.2.x series vastly improved support for theActiveX andComponent Object Model (COM)interface, andObject Linking and Embedding (OLE), though bugs were still being found. The delegation to interface using theimplements keyword was partly implemented, but was not complete as of March 2011[update].[1] Library support for ActiveX was also improved.
Another major feature was the internal linker for Win32, Win64, and Windows CE, which greatly improved linking time and memory use, and make the compile-link-run cycle in Lazarus much faster. The efficiency for smart-linking, ordead code elimination, was also improved.
Minor new features included improved DWARF (2/3) debug format support, and optimizations such astail recursion, omission of unneededstack frames and register-basedcommon subexpression elimination (CSE) optimization. A first implementation ofgeneric programming (generics) support also became available, but only experimentally.
The 2.4.x release series had a less clear set of goals than earlier releases. The unit system rewrite was postponed again, and the branch that became 2.4 was created to keep risky commits from 2.2 to stabilize it. Mostly these risky commits were more involved improvements to the new platforms, Mac PowerPC 64, Mac x86-64, iPhone, and many fixes to the ARM and x86-64 architectures in general, as well as DWARF.
Other compiler improvements includedwhole program optimization (WPO) anddevirtualization and ARMembedded-application binary interface (EABI) support.
Later, during the 2.2 cycle, a moreDelphi-like resource support (based on special sections in the binary instead of Pascal constants) was added. This feature, direly needed by Lazarus, became the main highlight of the branch.
Other more minor additions were amemory manager that improvedheap manager performance inthreaded environments, small improvements in Delphi compatibility such asOleVariant, and improvements ininterfacedelegation.
On January 1, 2010, Free Pascal 2.4.0 was released, followed on November 13, 2010, by bug fix release 2.4.2, with support forfor..in loops,sealed andabstract classes, and other changes.[2]
In January 2012, Free Pascal 2.6 was released. This first version from the 2.6 release series also supportedObjective Pascal on OS X andiOS targets and implemented many small improvements and bug fixes. In February 2013, FPC 2.6.2 was released. It containedNetBSD andOpenBSD releases for the first time since 1.0.10, based on fresh ports. In March 2014, the last point release in the 2.6 series, 2.6.4, was launched, featuring mostly database (fcl-db) updates.
Version 3.0.0 was released on November 25, 2015, and was the first major release since January 1, 2012.It introduced many new language features.[3]
Version 3.0.2 was released on February 15, 2017, and includes bug fixes and minor compiler updates.
Version 3.0.4 was released on November 28, 2017.
It includes many language improvements over previous versions, including an internal linker forExecutable and Linkable Format (ELF), Arm AARCH64 for iOS and Linux, a revived i8086 platform, extended libraries and much more.
The next major release, version 3.2.0, was published on June 19, 2020. It introduced many new language features, including generic routines, standard namespaces, managed records and expanded functionality for dynamic arrays, in addition to the advent of new standard units and the support of additional platforms.[4]
Version 3.2.2 was released on May 20, 2021, and supports macOS onAArch64 and naming of threads. Additionally it includes bug fixes and minor compiler updates.[5]
A release candidate, FPC 3.2.4-rc1, was available for test in June 2025.[6]
As of July 2025[update] development version 3.3.1 was available for download as filefpc.zip.[7] The most recent member of the archive (excepting a file stating the date the members offtp.zip were extracted) was dated 15 September 2023.
| Processor architecture | Operating system, device | Version 3.2.2 or 3.3.1 (Trunk) | Version 3.0.0 - 3.2.0 | Version 2.6.2 | Version 2.6.0 | Version 2.4.4 | Version 2.4.2 | Version 2.4.0 | Version 2.2.4 | Version 2.0.x | Version 1.0.x |
|---|---|---|---|---|---|---|---|---|---|---|---|
| i386 | DOS (GO32v2 extender) | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| FreeBSD | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |
| OpenBSD | Yes | Yes | Yes | No | No | No | No | No | No | Yes | |
| NetBSD | Yes | Yes | Yes | No | No | No | No | No | No | Yes | |
| Linux | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |
| macOS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | |
| OS/2 | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |
| Windows | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |
| Windows CE | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | |
| BeOS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |
| Haiku | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | |
| NetWare | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | |
| Solaris | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | Yes | |
| iPhone Sim | Yes | Yes | Yes | Yes | No | No | No | No | No | No | |
| QNX Neutrino | Yes | No | No | No | No | No | No | No | No | Yes | |
| Android | Yes | Yes | Yes | No | No | No | No | No | No | No | |
| AROS | Yes | Yes | No | No | No | No | No | No | No | No | |
| x86-64 | FreeBSD | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | No |
| OpenBSD | Yes | Yes | Yes | Unknown | Unknown | Unknown | Unknown | Unknown | Unknown | Unknown | |
| NetBSD | Yes | Yes | Yes | Unknown | Unknown | Unknown | Unknown | Unknown | Unknown | Unknown | |
| Linux | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Unknown | No | |
| macOS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | |
| Windows | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | |
| iPhone Sim | Yes | Yes | Yes | Yes | No | No | No | No | No | No | |
| AROS | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | No | |
| DragonFly BSD | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | No | |
| Solaris | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | No | |
| Haiku | Yes | Yes | No | No | No | No | No | No | No | No | |
| Android | Yes | Yes | No | No | No | No | No | No | No | No | |
| ARM | iOS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No |
| Game Boy Advance | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | |
| Nintendo DS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | |
| Linux | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Unknown | No | |
| Windows CE | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Unknown | No | |
| Android | Yes | Yes | Yes | No | No | No | No | No | No | No | |
| Embedded | Yes | Yes | Yes | No | No | No | No | No | No | No | |
| Embedded Rasp-Pi | Yes | Yes | No | No | No | No | No | No | No | No | |
| AROS | Yes | Yes | No | No | No | No | No | No | No | No | |
| AArch64 | Linux | Yes | Yes | Yes | No | No | No | No | No | No | No |
| iOS | Yes | Yes | Yes | No | No | No | No | No | No | No | |
| Android | Yes | Yes | No | No | No | No | No | No | No | No | |
| macOS | Yes | No | No | No | No | No | No | No | No | No | |
| AVR | Embedded | Yes | Yes | No | No | No | No | No | No | No | No |
| PowerPC | Linux | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No |
| macOS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | |
| Classic Mac OS | Yes | Yes | Yes | Yes | Yes | No | No | Yes | Yes | No | |
| AmigaOS 4 | Yes | Yes | Yes | Yes | Yes | Unknown | Unknown | Unknown | Yes | No | |
| MorphOS | Yes | Yes | Yes | Yes | Yes | Unknown | Unknown | Unknown | Yes | No | |
| AIX | Yes | Yes | Yes | Yes | No | No | No | No | No | No | |
| Wii | Yes | Yes | Yes | Yes | Yes | No | No | No | No | No | |
| PowerPC 64-bit | Linux | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No |
| macOS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | |
| AIX | Yes | Yes | Yes | Yes | No | No | No | No | No | No | |
| SPARC | Solaris | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | No |
| NetBSD | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | No | |
| Embedded | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | No | |
| Linux | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | No | |
| SPARC64 | Linux | Yes | Yes | Yes | Yes | No | No | No | No | No | No |
| RISC-V | Embedded | Yes | Yes | No | No | No | No | No | No | No | No |
| RISC-V64 | Embedded | Yes | Yes | No | No | No | No | No | No | No | No |
| Java virtual machine | Java | Yes | Yes | No | No | No | No | No | No | No | No |
| Android | Yes | Yes | No | No | No | No | No | No | No | No | |
| MIPS (BE and LE) | Linux | Yes | Yes | No | No | No | No | No | No | No | No |
| Embedded | Yes | Yes | No | No | No | No | No | No | No | No | |
| 8086 (16-bit) | DOS | Yes | Yes | No | No | No | No | No | No | No | No |
| Win16 | Yes | Yes | No | No | No | No | No | No | No | No | |
| Embedded | Yes | Yes | No | No | No | No | No | No | No | No | |
| m68k | Linux | Yes | Yes | No | No | No | No | No | No | No | Yes |
| NetBSD | Yes | Yes | No | No | No | No | No | No | No | Yes | |
| AmigaOS | Yes | Yes | No | No | No | No | No | No | No | Yes | |
| Atari TOS | Yes | Yes | No | No | No | No | No | No | No | Yeslimited cross-compiler only | |
| Palm OS | Yes | Yes | No | No | No | No | No | No | No | Unknown | |
| Z80 | Embedded | Yes | No | No | No | No | No | No | No | No | No |
| ZX Spectrum | Yes | No | No | No | No | No | No | No | No | No | |
| MSX-DOS | Yes | No | No | No | No | No | No | No | No | No | |
| WebAssembly | Web browsers | Yes | No | No | No | No | No | No | No | No | No |
Free Pascal also supports byte code generation for theJava Virtual Machine as of version 3.0.0 and targets both Oracle's Java and Google's Android JVM,[8] although Object Pascal syntax is not fully supported. Free Pascal 3.0.0 also supports ARMHF platforms like theRaspberry Pi, including ARMV6-EABIHF running on Raspbian. Work on 64-bit ARM has resulted in support for iOS in 3.0.0 as well. A native ARM Android target has been added, ending the formerly hacked ARM Linux target to generate native ARM libraries for Android. This makes porting Lazarus applications to Android (using Custom Drawn Interface[9]) easier. Since FPC 2.6.2,OpenBSD andNetBSD are supported on IA32 and X86_64 architectures. A new targetembedded has been added for usage without OS (ARM Cortex M and MIPS mainly). With InstantFPC it is possible to run Pascal programs, which are translated just in time, as Unix scripts orCGI back-end.
Ultibo core is an embedded or bare metal development environment for Raspberry Pi.[10] Ultibo is based on Free Pascal and developed under a modified version of Lazarus. The IDE is PC based but has been ported to Linux and Mac as well. Ultibo is an OS-less runtime and has support for most functions and allows the programmer full control over the hardware via the RTL units. The runtime implements multi-threaded, pre-emptive multitasking. The programmer can put threads on a specific CPU or let the runtime divide the load automatically or a mix of the two. Most Raspberry Pi models are supported including the A, B, A+ and B+ as well as the Raspberry Pi 2B, 3B, 4B/400/CM4 and Zero.[11]
Like most modern compilers, Free Pascal can be used with anintegrated development environment (IDE). Besides independent IDEs there are also plugins to various existing IDEs
Apart from a compiler and an IDE, Free Pascal provides the following libraries:
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