Fortran Intrinsics

This is a collection of extended descriptions of the Fortran intrinsics based on the reference document “Current F2018 Working Document as of April 2018”. Vendor-specific extensions are not included.



The standard documents and most vendor-supplied descriptions of the intrinsics are often very brief and concise to the point where the functionality of the intrinsics becomes obscure, particularly to someone unfamiliar with the procedure.

By describing the procedures here

  • in greater detail

  • with a working example

  • providing links to additional resources (including additional documents at and related discussions in Fortran Discourse)

these documents strive to clarify the intrinsics for Fortran programmers.

This is a community-driven resource and everyone is encouraged to contribute to the documents. For contribution guidelines see minibook guide and the following Copyright guidelines.

See Also

  • The Fortran stdlib project

  • fpm(1) packages, many of which are general-purpose libraries/modules

  • M_intrinsics a related project to leverage the descriptions here to generate man-pages and an OS-agnostic CLI (Command Line Interface) program. This includes a tar(1) and zip(1) file of man-pages and a self-contained Fortran program that lets you view the non-graphical plain ASCII portions of the documentation from a terminal interface.

Text Content Copyrights

Many of the documents presented here are modified versions of man-pages from the Fortran Wiki and as such are available under the terms of the GNU Free Documentation License GFDL with no invariant sections, front-cover texts, or back-cover texts.

If you contribute to this site by modifying the files marked as GFDL, you thereby agree to license the contributed material to the public under the GFDL (version 1.2 or any later version published by the Free Software Foundation, with no invariant sections, front-cover texts, or back-cover texts).

If you contribute new material you thereby agree to release it under the MIT license, and should indicate this by placing MIT on the specially-formatted last line. For example, change

###### fortran-lang intrinsic descriptions


###### fortran-lang intrinsic descriptions (License: MIT) @urbanjost

Written in Myst-Markdown