First steps with fpm¶

This tutorial covers the basic usage of the Fortran Package Manager (fpm) command line. It will cover the generation of a new project and the possibility to compile a project into an executable as well as the possibility to run the resulting program.

To start a new project with fpm use the fpm new command

❯ fpm new first_steps

By default fpm creates a git repository with a dummy project in the fpm standard layout

❯ cd first_steps
❯ tree .
.
├── README.md
├── app
│   └── main.f90
├── fpm.toml
├── src
│   └── first_steps.f90
└── test
    └── check.f90

3 directories, 5 files

This is everything we need to start our new project. First, we inspect the package manifest, fpm.toml, which is populated with stub entries for us:

fpm.toml¶

name = "first_steps"
version = "0.1.0"
license = "license"
author = "Jane Doe"
maintainer = "jane.doe@example.com"
copyright = "Copyright 2021, Jane Doe"
[build]
auto-executables = true
auto-tests = true
auto-examples = true
[install]
library = false

The package manifest contains all the required meta data for the new project. Next we checkout the main executable, app/main.f90, fpm has generated for us:

app/main.f90¶

program main
  use first_steps, only: say_hello
  implicit none

  call say_hello()
end program main

The program already uses a module from our library, which we can find in src/first_steps.f90:

src/first_steps.f90¶

module first_steps
  implicit none
  private

  public :: say_hello
contains
  subroutine say_hello
    print *, "Hello, first_steps!"
  end subroutine say_hello
end module first_steps

We can run the executable directly with the command fpm run:

❯ fpm run
...
 Hello, first_steps!

Similarly, fpm has already created a stub for testing, which can be invoked with fpm test:

❯ fpm test
...
 Put some tests in here!

Fpm will automatically track changes in your project when running your project using the run and test commands.

Summary

In this tutorial you learned how to

create a new project from the fpm command line
build and run your project executables with fpm
run tests with fpm