fortran2018-conditional-memory

Summary

A Fortran 2018 library for conditional (de-)allocation of allocatable objects of intrinsic types.

1. License
2. Software Requirements
3. Description
4. Build

License

This project's license is GPL-3.0. The whole license text can be found in LICENSE in the main directory of this repository. The brief version is as follows:

Copyright (C) 2022 Kevin Matthes

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

Software Requirements

Requirement	Type	Role
Doxygen	application	source code documentation
GFortran	application	Fortran 2018 compiler
Git	application	build artifact removal
Just	Rust binary	execution of the build instructions
Latexmk	application	LaTeX compilation of Doxygen manual
TeX Live (full)	package	LaTeX environment for Doxygen manual
Valgrind	application	memory leak detection

This library is written in Fortran 2018 such that its build requires a compiler supporting this standard. This project relies on GFortran therefore.

The library build is organised with Just. The corresponding .justfile does not only take care for the compilation of the library but also for its documentation and testing.

The documentation is generated by Doxygen. The configured output formats are listed in the following.

• HTML
• LaTeX
• UNIX manual pages

In order to finalise the LaTeX documentation, an appropriate LaTeX distribution is required. A full installation of TeX Live is recommended. This project employs Latexmk as LaTeX build manager for the manual finalisation.

There are unit tests for the library logic written in plain Fortran 2018 without requiring any further libraries. When running the tests, Valgrind will analyse their memory management.

Build artifacts are prevented from begin committed by the .gitignore this repository contains. It furthermore controls which files are going to be removed by git clean. Thus, it is the simplest solution to employ Git for the removal of build artifacts.

Description

This repository provides the source code for a library named libf18cndmem.a. The purpose of this library is the conditional allocation and deallocation of allocatable objects of Fortran intrinsic types. It is written in Free Form Fortran 2018.

As the deallocation of an allocatable object which is not already allocated will result in a runtime error, it needs to be checked whether the object to deallocate is allocated at all. The deallocation subroutines this library provides will take care about both this check and the deallocation, if required. All those subroutines are exposed with the generic interface cnddel which is an abbreviation of "Conditional Deallocation". At the moment, the following types are supported:

• character (default)

Fortran 2018 has automatic reallocation features which allow for a convenient and comprehensive coding style. Under certain circumstances, it might not be obvious if an allocatable object is already allocated such that the automatic reallocation on intrinsic assignment could be processed. Then, it need to be tested whether there is already a memory region allocated for the respective object. If not so, an according amount of memory needs to be allocated before the assignment can be performed. This library provides a counterpart to the conditional deallocation, named cndall, to check whether some memory was already allocated and to assign the intended object to the target object. The name cndall is an abbreviation of "Conditional Allocation". At the moment, the following types are supported:

• character (default)

Build

The build routine is organised by Just and defined in the .justfile in the repository root. To build the library, one of the following instructions can be executed.

just b
just build
just l
just library

In addition, an automatic source code documentation with Doxygen is configured. One of the following commands will invoke the compilation.

just d
just doxygen

The correctness of this library is ensured by a set of unit tests. They are furthermore analysed for their memory management by Valgrind. By calling for the Valgrind analysis, the unit tests are executed implicitly. This can be done with one of the following commands.

just v
just valgrind

If the compilation of both the library and its documentation is wished, the following instructions can be executed. This will also run all unit tests.

just
just a
just all