Notice: This page contains information for the legacy Phidget21 Library. Phidget21 is out of support. Bugfixes may be considered on a case by case basis. Phidget21 does not support VINT Phidgets, or new USB Phidgets released after 2020. We maintain a selection of legacy devices for sale that are supported in Phidget21. We recommend that new projects be developed against the Phidget22 Library.
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Language - C
Support
C/C++ has a complete API and sample code for all Phidgets devices. You can also view a complete list of the status for our supported languages.
If this is your first time working with a Phidget, we suggest starting with the Getting Started page for your specific device. That page will walk you through installing drivers and libraries for your operating system, and will then bring you back here to use C/C++ specifically.
C/C++ can be developed with various Windows compilers (including Borland), Mac OSX, and Linux.
Quick Downloads
Just need the C/C++ drivers, libraries, and examples? Here they are:
C/C++ API Documentation:
- C/C++ API Manual Download or (HTML online version)
- General API (more help on functions common to all Phidgets)
- Device Specific APIs (more help on functions specific to your Phidget)
C/C++ Example Code:
Libraries and Drivers:
- 32 bit Windows (drivers, with libraries)
- 64 bit Windows (drivers, with libraries)
- Borland C++ Libraries (You also need one of the two Windows drivers above)
- General Linux Libraries ( Linux Library Setup Instructions)
- General Mac OSX Libraries ( Mac OSX Library Setup Instructions)
Getting Started (Windows)
Run The Examples
A good way to learn to use Phidgets is to run and modify existing examples. You can find the C/C++ API and example code here:
To run the example code, you'll need to find the source code for your specific device within the example package. Then, compile the code under your platform and run it. This will allow you to:
- Make sure your libraries are properly linked
- Go from source code to a test application as quickly as possible
The Phidget examples were written using Visual C++ 2005. They also work well in other, similar environments such as Visual Studio.
Specific setup for many other compilers is covered below. Often, you can just import the example as an existing project, but if you are having trouble it might help to read the Writing Your Own Code section below for your specific compiler.
Follow The Examples
The Hello World example has this general structure so you can follow along. We also have an in-depth general introduction to writing Phidget code (like open, read data, etc), as well as the {{{3}}} for specific syntax:
// ----- Event and Other Functions ----- Create any Language-Specific Functions (exception handling) Create General Attach, Detach, and Error Handling Functions:
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{{{1}}} | |
// ----- Main Code -----
Close Device Delete Device
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{{{2}}} |
Write Your Own Code (Windows)
- C/C++ API (This is the complete set of functions you have available for all Phidgets)
- Device Specific APIs - The one for your Phidget can be found in its user guide.
To learn the details behind opening, configuring, using, and closing your Phidget, try the General Phidget Programming page. That page also describes using the Phidget in an event-driven manner and in a traditional manner, both of which are available in C/C++.
These Windows sections below need additional information |
General Windows Library Setup
In addition to actually creating code to drive your Phidget, you will also need to properly link the Phidget C/C++ libraries, which are included with the drivers above. Most compilers provide their own documentation on how to link external libraries. (Note that for Borland, you'll need a different library, which you can find in the Borland section below).
Then, in your code, you usually need to include the Phidget library specifically:
#include "phidget21.h"
Visual C++ 2005 Library Setup
To link libraries in Visual C++ 2005:
- Generate a new C/C++ console project with a descriptive name such as PhidgetTest.
- Copy phidget21.h and phidget21.lib from the VC/VC++/Borland examples and add them to your project directory.
- Open the project properties window.
- Navigate to Configuration Properties | Linker | Input.
- Edit the additional dependencies and add “phidget21.lib”.
The project now has access to the Phidget21 function calls and you are ready to begin coding.
Borland C/C++ Library Setup
To link libraries in Borland C/C++:
Make sure to download the additional Borland-specific libraries in addition to the drivers you already have through the Getting Started page for your device:
Create and Build Your Project
With the libraries linked properly in your compiler, you can consult the following resources for help with writing code:
- C/C++ API Manual Download or (HTML online version)
- General API (more help on functions common to all Phidgets)
- Device Specific APIs (more help on functions specific to your Phidget)
- The page with general programming concepts for Phidgets
Build and compile your project with the properly linked libraries as you would any project on your specific compiler.
Getting Started (MacOS/Linux)
Run The Examples
One good way to start developing your application is to run and modify existing examples. You can find the C/C++ API and example code here:
To run the example code, you'll need to find the source code for your specific device. Then, compile the code under your platform and run it. This will allow you to:
- Make sure your libraries are properly linked, as above
- Go from source code to a test application as quickly as possible
Compiling and linking against the Phidgets Library for the example code can be done in the following ways:
To build on Linux:
gcc example.c -o example -lphidget21
To build on MacOS (for example, depending on the Headers location):
gcc example.c -o example -framework Phidget21 -I/Library/Frameworks/Phidget21.framework/Headers
Follow The Examples
Setting up the Libraries
Before you can use the Phidget, you must include a reference to the library header.
#include <phidget21.h>
This assumes that the compiled libraries has been set up properly.
- To set them up on Mac OSX, follow the Getting Started page for your specific device
- To set them up on Linux, compile and install them as explained on the main Linux page
Write Your Own Code (Mac OSX/Linux
- C/C++ API (This is the complete set of functions you have available for all Phidgets)
- Device Specific APIs - The one for your Phidget can be found in its user guide.
To learn the details behind opening, configuring, using, and closing your Phidget, try the General Phidget Programming page. That page also describes using the Phidget in an event-driven manner and in a traditional manner, both of which are available in C/C++.
Create and Build Your Project
With the libraries linked properly in your compiler, you can consult the following resources for help with writing code:
- C/C++ API Manual Download or (HTML online version)
- General API (more help on functions common to all Phidgets)
- Device Specific APIs (more help on functions specific to your Phidget)
- The page with general programming concepts for Phidgets
Compiling and linking against the Phidgets Library for the example code can be done in the following ways:
To build on Linux:
gcc example.c -o example -lphidget21
To build on MacOS (for example, depending on the Headers location):
gcc example.c -o example -framework Phidget21 -I/Library/Frameworks/Phidget21.framework/Headers
Building your Project
Describe the different ways a project could be built and packaged using this language.
Development Environments and Compilers
Describe each major compiler and notable differences or important information. (eg. framework versions) If there are known issues/workarounds mention them and link to the corresponding issue at the bottom of the page.
This section may or may not be covered in the different compilers section in the Getting Started (Windows) section above. If it can be covered by a combination of the Getting Started section above, and the Common Problems section below, delete this section... |
Common Problems and Solutions/Workarounds
Here you can put various frequent problems and our recommended solutions.