Language - C

From Phidgets Support
Revision as of 16:21, 10 November 2011 by Cora (talk | contribs)

C/C++ has a complete API and sample code for all Phidgets devices.
For a complete list of our supported languages and their support status, click here.

C/C++ can be developed with various Windows compilers (including Borland), Mac OSX, and Linux.

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.


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.

TO BE COMPLETED

Drivers, Libraries and Resources

Before you can run your program, you need to set up the proper environment and get the necessary files off the Phidgets website. Visit the drivers section at www.phidgets.com and get the latest:

You will need the Phidget Framework to use and to program with Phidgets. We also recommend that you download the following reference materials:

You may want to have these pages open while working through these instructions.

Getting Started (Windows)

The Phidget examples were written using Visual C++ 2005 and this tutorial assumes its use. Other environments such as other versions of Visual Studio work as well and would be set up in a similar manner. Borland C also requires the phidget21bcc.lib file provided at the Phidgets website. Consult your compiler documentation for specific details on how to link to external 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 we are ready to begin coding.

Setting up the Libraries

Before you can use the Phidget, you must include a reference to the library header. 

  #include "phidget21.h"

Afterwards, the Phidget object will need to be declared and then initialized. For example, we can declare a PhidgetInterfaceKit inside our main function with: 

  int _tmain(int argc, _TCHAR* argv[])
  {
     CPhidgetInterfaceKitHandle ifKit = 0; //Declare an InterfaceKit handle
     CPhidgetInterfaceKit_create(&ifKit);  //Create the InterfaceKit object
   
     //More code goes here
     return 0;
  }

The object name for any type of Phidget is listed in the API manual. Every type of Phidget also inherits functionality from the Phidget base class.

You now have the libraries set up for either running the provided examples, or writing your own code, as below.

Developing Code (Windows)

Running 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

Writing Your Own Code

You can use a Phidget in code by essentially by:

  1. Opening it,
  2. Setting it up,
  3. Doing things with it (like reading data), and
  4. Closing it.

These steps are generally outlined for all devices and languages on the General Phidget Programming page. The General Phidget Programming page also introduces using the Phidget in an event-driven manner or in a traditional manner, both of which are available in C/C++.

The complete set of functions you have available for all Phidgets can be found in the C/C++ API.

If you are looking for more information about a particular function, we provide that as well. You can find more description on any function either in:

  1. Our API Overview which describes the set of calls common to all Phidgets, or
  2. The Device API page for calls available only on your specific Phidget.

Getting Started (MacOS/Linux)

Setting up the Libraries

Before you can use the Phidget, you must include a reference to the library header. 

  #include <phidget21.h>

Afterwards, the Phidget object will need to be declared and then initialized. For example, we can declare a PhidgetInterfaceKit inside our main function with: 

  int main(int argc, char* argv[])
  {
    CPhidgetInterfaceKitHandle ifKit = 0;
    CPhidgetInterfaceKit_create(&ifKit);
    //More code goes here
    return 0;
  }

The object name for any type of Phidget is listed in the API manual. Every type of Phidget also inherits functionality from the Phidget base class.

Developing Code (Mac OSX/Linux)

Running Examples

Writing Your Own Code

You can use a Phidget in code by essentially by opening it, setting it up, doing things with it, and closing it. These steps are outlined at a high-level for all devices and languages on the General Phidget Programming page.

The complete set of functions you have available can be found in the C/C++ API. More description about parts of the API can be found in our API Overview general to all devices, or, where the calls are specific to a device, on the Device API page for your specific Phidget.

Compiling Your Program

Compiling and linking against the Phidgets Library can be done in the following ways:

  • To build on Linux:
gcc example.c -o example -lphidget21
  • To build on MacOS:
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 using this language.

Common Problems and Solutions/Workarounds

Here you can put various frequent problems and our recommended solutions.

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