Editing Modula-3 (section)

==Standard library features==
Continuing a trend started with the [[C (programming language)|C]] language, many of the features needed to write real programs were left out of the language definition and instead provided via a [[standard library]] set. Most of the interfaces below are described in detail in<ref name=DecSrcRr113>[http://apotheca.hpl.hp.com/ftp/pub/dec/SRC/research-reports/SRC-113.pdf Some Useful Modula-3 Interfaces] {{Webarchive|url=https://web.archive.org/web/20160304040009/http://apotheca.hpl.hp.com/ftp/pub/dec/SRC/research-reports/SRC-113.pdf |date=2016-03-04 }} Jim Horning, Bill Kalsow, Paul McJones, Greg Nelson. [[DEC Systems Research Center]] (SRC) Research Report 113 (December 1993)</ref>

Standard libraries providing the following features. These are called standard interfaces and are required (must be provided) in the language.
* Text: Operations on immutable string references, called <code>TEXT</code>s
* Thread: Operations relating to threading, including <code>MUTEX</code>, condition variable, and thread pausing.  The threading library provides pre-emptive threads switching
* Word: Bitwise operations on unsigned integers (or machine words). Normally implemented directly by the compiler
* Floating-point interfaces
Some recommended interfaces implemented in the available implementations but are not required
* Lex: For parsing number and other data
* Fmt: Formatting various datatypes for printing
* Pkl (or Pickle): [[Object serialization]] of any reference types reachable by the garbage collector
* Table: Generic modules for [[Map (computer science)|maps]]

As in C, I/O is also provided via libraries, in Modula-3 called <code>Rd</code> and <code>Wr</code>. The object-oriented design of the Rd (readers) and Wr (writers) libraries is covered in detail in the book by Greg Nelson. An interesting aspect of Modula-3 is that it is one of few programming languages which standard libraries have been formally verified not to contain various types of bugs, including locking bugs. This was done under the auspices of the Larch/Modula-3 (see [[Larch family]])<ref name=DecSrcRr072>[http://apotheca.hpl.hp.com/ftp/pub/dec/SRC/research-reports/SRC-072.pdf LM3] {{Webarchive|url=https://web.archive.org/web/20160303215535/http://apotheca.hpl.hp.com/ftp/pub/dec/SRC/research-reports/SRC-072.pdf |date=2016-03-03 }} Kevin D. Jones. [[DEC Systems Research Center]] (SRC) Research Report 72 (June 1991)</ref> and [[Extended static checking]]<ref name=CompaqSrcRr159>[http://apotheca.hpl.hp.com/ftp/pub/dec/SRC/research-reports/SRC-159.pdf Extended Static Checking] {{Webarchive|url=https://web.archive.org/web/20170705054838/http://apotheca.hpl.hp.com/ftp/pub/dec/SRC/research-reports/SRC-159.pdf |date=2017-07-05 }}  David L. Detlefs, K. Rustan M. Leino, Greg Nelson, [[James B. Saxe]]. Compaq SRC Research Report 159 (December 1998)</ref> projects at [[DEC SRC|DEC Systems Research Center]].