View source for Portable C Compiler

{{Short description|C compiler for Unix and Unix-like operating systems}}
{{Infobox software
| name = Portable C Compiler
| logo = 
| screenshot = 
| caption = 
| author = [[Stephen C. Johnson]]
| developer = [[AT&T Bell Laboratories]]
| released = {{Start date and age|1979}}
| latest release version = 1.1.0
| latest release date = {{Start date and age|2014|12|10}}
| latest preview version = 
| latest preview date = 
| operating system = [[Unix]] and [[Unix-like]]
| programming language = [[C (programming language)|C]]
| genre = [[C (programming language)|C]] [[Compiler]]
| license = [[BSD License]]
| website = http://github.com/portablecc
}}
The '''Portable C Compiler''' (also known as '''pcc''' or sometimes '''pccm''' - portable C compiler machine) is an early [[compiler]] for the [[C (programming language)|C programming language]] written by [[Stephen C. Johnson]] of [[Bell Labs]] in the mid-1970s,<ref>{{cite book |author=Johnson, S.C. |title=Proceedings of the 5th ACM SIGACT-SIGPLAN symposium on Principles of programming languages - POPL '78 |chapter=A portable compiler: Theory and practice |date=1978 |pages=97–104 |author-link=Stephen C. Johnson |doi=10.1145/512760.512771 |s2cid=14390804|doi-access=free }}</ref> based in part on ideas proposed by [[Alan Snyder (computer scientist)|Alan Snyder]] in 1973,<ref>{{cite web |author=Snyder, A. |year=1975 |title=A Portable Compiler for the Language C |work=Master's Thesis. MIT, Cambridge, Mass. |url=http://www.lcs.mit.edu/publications/specpub.php?id=717 |author-link=Alan Snyder (computer scientist) |access-date=2006-07-19 |archive-url=https://web.archive.org/web/20060905200607/http://www.lcs.mit.edu/publications/specpub.php?id=717 |archive-date=2006-09-05 |url-status=dead}}</ref><ref>{{cite book |author=Johnson, S.C. |year=1981 |title=A Tour Through the Portable C Compiler |series=Unix Programmer's Manual, 7th edition, Volume 2 |publisher=Holt, Rinehart and Winston |isbn=0-03-061743-X |url=http://citeseer.ist.psu.edu/johnson81tour.html |author-link=Stephen C. Johnson}}</ref>
and "distributed as ''the'' C compiler by Bell Labs... with the blessing of [[Dennis Ritchie]]."<ref name="stroustrup"/>

Being one of the first compilers that could easily be adapted to output code for different computer architectures, the compiler had a long life span. It debuted in [[Seventh Edition Unix]] and shipped with [[Berkeley Software Distribution|BSD Unix]] until the release of [[4.4BSD]] in 1994, when it was replaced by the [[GNU C Compiler]]. It was very influential in its day, so much so that at the beginning of the 1980s, the majority of C compilers were based on it.<ref>{{cite web |author=Ritchie, Dennis M. |year=1993 |title=The development of the C language |work=The second ACM SIGPLAN conference on History of programming languages. Cambridge, Massachusetts. |pages=201–208 |url=http://plan9.bell-labs.com/who/dmr/chist.html |access-date=2008-12-30 |quote=At the start of the decade, nearly every compiler was based on Johnson's ''pcc''; by 1985 there were many independently-produced compiler products. |author-link=Dennis Ritchie}}</ref> Anders Magnusson and Peter A Jonsson restarted development of pcc in 2007, rewriting it extensively to support the [[C99]] standard.<ref name=pcc-history>{{cite web
|url        = http://pcc.ludd.ltu.se/pcc_history/
|title      = pcc history
|work       = pcc - portable c compiler
|date       = 2010-06-21
|access-date = 2012-06-26
}}</ref>

==Features==
Key features of pcc are its [[Software portability|portability]] and improved diagnostic capabilities. The [[compiler]] was designed so that only a few of its [[source code|source]] [[computer file|file]]s are [[machine-dependent]]. It is relatively robust to [[syntax error]]s and performs more thorough validity checks than its contemporaries.{{According to whom|date=October 2018}}

The first C compiler, written by [[Dennis Ritchie]], used a [[recursive descent parser]], incorporated specific knowledge about the [[PDP-11]], and relied on an optional machine-specific optimizer to improve the assembly language code it generated. In contrast, Johnson's pccm was based on a [[yacc]]-generated parser and used a more general target machine model. Both compilers produced target-specific assembly language code which they then assembled to produce linkable object modules.

Later versions of PCC, known within Bell Labs as "QCC" and "RCC," supported other target architecture models.{{citation needed|date=June 2012}}

The language that PCC implements is an extended version of [[C (programming language)#K&R C|K&R C]] that [[Bjarne Stroustrup]] has called "Classic C", incorporating the <code>void</code> return type (for functions that don't return any value), enumerations and structure assignment.<ref name="stroustrup">{{cite report |first=Bjarne |last=Stroustrup |author-link=Bjarne Stroustrup |title=Sibling rivalry: C and C++ |publisher=AT&T Labs |number=TD-54MQZY |year=2002 |url=http://stroustrup.com/sibling_rivalry.pdf}}</ref>

==Current version==
A new version of pcc, based on the original by Steve Johnson, is maintained{{when|date=May 2024}} by Anders Magnusson.<ref name=pcc-history/> The compiler is provided under the [[BSD licence]] and its development is funded by a non-profit organization called BSD Fund. According to Magnusson:

{{quotation|The big benefit of it (apart from that it's BSD licensed, for license geeks) is that it is fast, 5-10 times faster than gcc, while still producing reasonable code. <...> [I]t is also quite simple to port...|Anders Magnusson<ref>{{cite web
|url        = http://undeadly.org/cgi?action=article&sid=20070915195203&mode=expanded
|title      = BSD Licensed PCC Compiler Imported
|first      = Mike
|last       = Erdely
|work       = [[OpenBSD Journal]]
|date       = 2007-09-15
|access-date = 2011-12-17
}}</ref>}}
This new version was added to the [[NetBSD]] [[pkgsrc]] and [[OpenBSD]] source trees in September 2007,<ref>{{cite mailing list
|url         = http://marc.info/?l=openbsd-cvs&m=118988004013923&w=2
|title       = CVS: cvs.openbsd.org: src
|first       = Otto
|last        = Moerbeek
|mailing-list = openbsd-cvs
|date        = 2007-09-15
}}</ref> and later into the main [[NetBSD]] source tree.<ref>{{cite mailing list
|url         = http://mail-index.netbsd.org/source-changes/2007/09/20/0005.html
|title       = CVS commit: src/dist/pcc
|first       = David
|last        = Brownlee
|mailing-list = source-changes
|date        = 2007-09-20
}}</ref> There had been some speculation that it might eventually be used to supplant the GNU C Compiler on BSD-based operating systems,<ref>{{cite web
|url        = http://developers.slashdot.org/article.pl?sid=07/09/17/1451239
|work       = [[Slashdot|/.]]
|title      = GCC Compiler Finally Supplanted by PCC?
|date       = 2007-09-17
}}</ref> though [[FreeBSD]]<ref>{{cite web |url=https://www.phoronix.com/scan.php?page=news_item&px=MTEwMjI |title=FreeBSD 10 To Use Clang Compiler, Deprecate GCC |last=Larabel |first=Michael |publisher=[[Phoronix]] |date=12 May 2012 |url-status=live |archive-url=https://web.archive.org/web/20150410143519/http://www.phoronix.com/scan.php?page=news_item&px=MTEwMjI |archive-date=10 April 2015 |access-date=23 April 2015}}</ref><ref>{{cite mailing list |url=http://lists.freebsd.org/pipermail/freebsd-current/2012-November/037610.html |title=HEADS UP: Clang now the default on x86 |date=5 November 2012 |access-date=23 April 2015 |last=Brooks |first=Davis}}</ref> and [[NetBSD]]<ref>{{cite mailing list |url=http://mail-index.netbsd.org/tech-toolchain/2013/10/17/msg002117.html |title=Importing LLVM/Clang |date=17 October 2013 |access-date=23 April 2015 |last=Joerg |first=Sonnenberger}}</ref> are both looking to [[Clang]] as a potential replacement, and [[Theo de Raadt]] of [[OpenBSD]] asserts that pcc is not ready yet to be a gcc replacement, and the disposal of gcc is not top priority.<ref>{{cite web
|url      = http://www.thejemreport.com/more-on-openbsds-new-compiler/
|title      = More on OpenBSD's new compiler
|first      = Jem
|last      = Matzan
|work      = The Jem Report
|date      = 2007-10-15
|access-date      = 2011-12-17
|quote      = But that’s never really been the agenda, see. Some people think we hate GNU code. But the thing is we hate large code, and buggy code that upstream does not maintain. That’s the real problem… gcc gets about 5-6% slower every release, has new bugs, generates crappy code, and drives us nuts. This is just an attempt to see if something better can show up.
|archive-url      = https://web.archive.org/web/20120104122624/http://www.thejemreport.com/more-on-openbsds-new-compiler/
|archive-date      = 2012-01-04
|url-status      = dead
}}</ref> On December 29, 2009, pcc became capable of building a functional x86 [[OpenBSD]] kernel image.<ref>{{cite web
|url        = http://undeadly.org/cgi?action=article&sid=20091228231142
|title      = Call for testing: pcc and the OpenBSD kernel
|first      = Paul
|last       = de Weerd
|work       = [[OpenBSD Journal]]
|date       = 2009-12-29
|access-date = 2011-12-17
}}</ref>

pcc version 1.0 was released on 1 April 2011.<ref>{{cite web
|url        = http://pcc.ludd.ltu.se/1.0_release/
|title      = 1.0 Release
|first      = Anders
|last       = Magnusson
|work       = Portable C Compiler
|date       = 2011-04-01
|access-date = 2011-12-17
}}</ref>
As of this release, the compiler supports [[x86]] and [[x86-64]] processor architectures and runs on [[NetBSD]], [[OpenBSD]], [[FreeBSD]], various [[Linux]] distributions, and [[Microsoft Windows]].<ref>{{cite web
|url        = http://www.bsdfund.org/projects/pcc/
|title      = BSD Fund: pcc fund
|work       = bsdfund.org
|date       = 2011-04-01
|access-date       = 2012-06-26
|archive-url       = https://web.archive.org/web/20090105234407/http://www.bsdfund.org/projects/pcc/
|archive-date      = 2009-01-05
|url-status        = dead
}}</ref>
Further development, including support for more architectures, and [[FORTRAN 77]] and [[C++]] front ends, is continuing as of 2022.

PCC was removed from the OpenBSD [[source tree]] in 2012.<ref>{{cite web |url=http://marc.info/?l=openbsd-cvs&m=133423160431049&w=2 |author=Paul Irofti |date=2012-04-12 |title=CVS: cvs.openbsd.org: src}}</ref> Development on it had stalled and no maintainer had stepped up to develop it into something that could make a practical alternative to [[GNU Compiler Collection]].<ref>{{cite web |url=http://marc.info/?l=openbsd-misc&m=134005622621532&w=2 |title=Re: Story behind PCC's removal? |author=Peter Hessler |date=2012-06-18}}</ref><ref>{{cite web |url=http://marc.info/?l=openbsd-misc&m=137530560232232&w=2 |title=Compilers in OpenBSD |author=Miod Vallat |date=2013-07-31}}</ref>

The latest version of pcc, namely 1.1.0, was released on 10 December 2014.<ref>{{cite web
|url        = http://pcc.ludd.ltu.se/ftp/pub/pcc-releases/
|title      = 1.1.0 Release
|first      = Anders
|last       = Magnusson
|work       = Portable C Compiler
|date       = 2014-12-10
|access-date = 2022-04-22
}}</ref>

==See also==
{{Portal|Free and open-source software}}
*[[Amsterdam Compiler Kit]]
*[[Clang]]
*[[Open Watcom]]

==References==
{{Reflist|30em}}

==External links==
* {{official website}}
* [http://www.tuhs.org/Archive/Applications/Portable_CC/ Archive at TUHS]
* [[GitHub]] repository [https://github.com/IanHarvey/pcc/ with a copy of the original sources]
* Another GitHub repository [https://github.com/neonkore/pcc with more up-to-date sources]

{{CProLang}}
{{NetBSD}}

[[Category:C (programming language) compilers]]
[[Category:Free and open source compilers]]
[[Category:Software using the BSD license]]
[[Category:OpenBSD]]<!-- 2007-09-15/2012-04-12-->
[[Category:NetBSD]]<!-- 2007-09-20/present (as of 2019-08-21) -->