Linux Simple I/O Library

libsimpleio is an attempt to encapsulate (as much as possible) the ugliness of Linux I/O device access. It provides services for the following types of I/O devices:

• Industrial I/O Subsystem A/D (Analog to Digital) Converter Devices
• Industrial I/O Subsystem D/A (Digital to Analog) Converter Devices
• GPIO (General Purpose Input/Output) Pins
• Raw HID (Human Interface Device) Devices
• I²C (Inter-Integrated Circuit) Bus Devices
• Labview LINX Remote I/O Devices
• PWM (Pulse Width Modulated) Output Devices
• Remote I/O Protocol Devices
• Serial Ports
• SPI (Serial Peripheral Interface) Bus Devices
• Stream Framing Protocol Devices
• TCP and UDP over IPv4 Network Devices
• Watchdog Timer Devices

Although libsimpleio was originally intended for Linux microcomputers such as the Raspberry Pi, it can also be useful on larger desktop Linux systems.

The C wrapper functions exported by libsimpleio all follow the same uniform pattern:

• All C wrapper functions are proper procedures (void f() in C).
• All input arguments of primitive types (int, float, etc.) are passed by value.
• All output arguments of primitive types are passed by reference (int *, float *, etc.).
• All composite types are passed by reference.
• int32_t is used wherever possible for int and bool arguments.

All of the C wrapper functions are declared between _BEGIN_STD_C and _END_STD_C for C++. Binding modules are provided for Ada, C#, Java, and Free Pascal. Additional source code libraries are provided for Ada, C++, C#, Java, and Free Pascal that define OOP (Object Oriented Programming) classes for libsimpleio.

News

• 8 January 2020 -- Added LINUX_errno(). Added libmodbus bindings and objects for Ada.
• 31 January 2020 -- Added .gpr project files to ada/programs/libsimpleio/, ada/programs/libsimpleio/mcp2221/, and ada/programs/libsimpleio/remoteio to allow building native programs with just gprbuild, using a command like:

  
  gprbuild libsimpleio.gpr -p test_userled
  

  Reworked Ada make files to allow building Windows applications in Windows Subsystem for Linux. Until now, using the make files on Windows required using Cygwin.
• 1 February 2020 -- Added links to Make With Ada projects.
• 2 February 2020 -- Flattened the csharp/ directory tree.
• 7 February 2020 -- Added .Net Core 3.1 project templates for both libsimpleio and libremoteio. Install these from NuGet with the following commands:

  
  dotnet new -i libsimpleio-templates
  dotnet new -i libremoteio-templates
  

• 10 February 2020 -- Renamed NuGet package libsimpleio-standard to libsimpleio. Renamed NuGet package libremoteio-standard to libremoteio. Dropped support for building .Net Framework applications with csc.exe.
• 12 February 2020 -- Added Visual Studio project templates for libsimpleio and libremoteio for C# console applications for .Net Core and .Net Framework.
• 25 February 2020 -- Added support for building NuGet C# .Net Core application packages.
• 3 March 2020 -- Modified libsimpleio.dll to use IO.Objects.libsimpleio.Device.Designator instead of chip and channel to select ADC inputs, DAC outputs, GPIO pins, I²C buses, PWM outputs, and SPI slave selects.
• 30 April 2020 -- Added popen() wrappers LINUX_popen_read(), LINUX_popen_write() and LINUX_pclose(). Added Ada packages Email_Sendmail and Email_Mail, for sending email messages via /usr/sbin/sendmail and /usr/bin/mail respectively.
• 15 May 2020 -- Autogenerate API documentation .pdf files from libremoteio.dll.chm and libsimpleio.dll.chm. Include API documentation files (both .chm and .pdf) in the NuGet packages.
• 12 September 2020 -- Added or refined email services for Ada, C#, and Free Pascal. This work resulted from a lengthy period of experimentation with sending email from a Linux embedded system.
• 18 September 2020 -- Modified udev rule handling for native Linux systems. The rules and their helper scripts are now installed to /usr/local/share/libsimpleio/udev/. If you install from a source checkout, you now need to do make install_udev_rules after make install in order to install some symbolic links in /etc/udev/rules.d.
  Added a NuGet local package feed to libsimpleio. You need to manually add an entry to the packageSources block in NuGet.Config (found at .config/NuGet/NuGet.Config on Linux or %HOMEDRIVE%%HOMEPATH%\AppData\Roaming\NuGet\NuGet.Config on Windows) in order to use the local package feed. You should also comment out the entry for nuget.org, especially if you need to build .Net applications offline from the Internet.
• 30 October 2020 -- Added initial support for the Go programming language, including a build framework using gccgo and enough packages to support GPIO pins.
• 13 November 2020 -- Overhauled the C++ code base. Started implementing C++ Remote I/O support. Upgraded from .Net Core 3.1 to .Net 5.0.
• 24 November 2020 -- Made many improvements, cleanups, and reorganizations of the Remote I/O Protocol client implementations for Ada, C++, and Free Pascal.

Documentation

The user manual for libsimpleio is available at UserManual.pdf.

The man pages specifying the libsimpleio API are available at libsimpleio.html.

Git Repository

The source code is available at:

https://github.com/pmunts/libsimpleio

Use the following command to clone it:

git clone https://github.com/pmunts/libsimpleio.git

Package Repository

Prebuilt packages for Debian Linux are available at:

Make With Ada Projects

• 2017 Ada Embedded Linux Framework
• 2019 Modbus RTU Framework for Ada (Prize Winner!)

I am available for custom system development (hardware and software) of products using ARM Linux or other microcomputers.