Language - C

C++ is a general purpose, cross-platform programming language with a vast user base.

Getting started with C/C++

If you are new to writing code for Phidgets, we recommend starting by running, then modifying existing examples. This will allow you to:

• Make sure your libraries are properly linked
• Go from source code to a test application as quickly as possible
• Ensure your Phidget is hooked up properly

Instructions are divided up by operating system. Choose:

• Windows 2000 / XP / Vista / 7
• OS X
• Linux (including PhidgetSBC)

Windows (2000/XP/Vista/7)

Description of Library Files

C/C++ programs on Windows depend on three files, which the installers in Quick Downloads put onto your system:

• phidget21.dll contains the actual Phidget library, which is used at run-time. By default, it is placed in C:\Windows\System32.
• phidget21.lib is used by your compiler to link to the dll. Your compiler has to know where this file is, by default our installer puts phidget21.lib into C:\Program Files\Phidgets, so you can either point your compiler to that location, or copy and link to it in a directory for your project workspace. phidget21.lib is written to be compatible with most compilers - but your specific compiler may need a different format. Check our documentation for your specific compiler for details. Please note that we provide versions of the phidget21.lib that are specifically optimized for 32-bit or 64-bit systems. If you are using a 64 bit versions of Windows, the phidget21.lib is placed in C:\Program Files\Phidgets; The 32 bit version of phidget21.lib is placed in C:\Program Files\Phidgets\x86.
• phidget21.h lists all the Phidget API function calls available to your code. Your compiler also has to know where this file is. By default, our installer puts phidget21.h into C:\Program Files\Phidgets so you can either point your compiler to that location, or copy and link to it in a directory for your project workspace.

If you do not want to use our installer, you can download all three files and manually install them where you want; refer to our Manual Installation Instructions.

Running the examples and writing your own code can be fairly compiler-specific, so we include instructions for Visual Studio 2005/2008/2010, Visual Studio 2003, Visual Studio 6, Borland, Cygwin/MinGW, and Dev C++.

Visual Studio

C++/CLI (which used to be called Managed C++) is very different from mainstream C/C++. If you must use C++/CLI, consider calling the Phidget .NET library, instead of the C API normally used from C/C++. We have no documentation for using C++/CLI.

Microsoft makes free versions of Visual Studio available known as Express Editions. The Express editions are suitable for most applications, but are limited in features for more complex applications. Please see Microsoft Visual Studio for more information.

Visual Studio 2005/2008/2010

Use Our Examples

To run the examples, you first download the examples and unpack them into a folder. To load all projects in Visual Studio, go to File → Open → Project → Solution, and open Visual Studio Phidgets Examples.sln in the VCpp folder of the examples.

Since the examples were written in Visual Studio 2005, if you are opening the examples in Visual Studio 2008/2010, you will need to go through the Visual Studio Conversion Wizard to open and convert the 2005 project.

This will load all of the examples available for C/C++. The easiest way to confirm that your environment is set up properly will be to compile and run the HelloWorld C/C++ example.

Start by setting the HelloWorld project as your start up project.

To run the example, click on Debug → Start Debugging. Please note that the projects, by default try to find the phidget21.h and phidget21.lib in the $(SystemDrive)\Program Files\Phidgets. If you have these files installed in another location, please change the path to the file's location accordingly. Please see the Write Your Own Code section for details.

This program will detect for devices that are attached/detached on the computer. Go ahead, and attach or detach your devices! Here is an example output:

If you have a 64-bit computer (and operating system) then you may also need to adjust the platform. You can do this by selecting x64 from the following drop down menu:

If x64 is not a selectable option then go into the Configuration Manager and create it by selecting New... and copying the settings from Win32. You should now be able to select x64 and run the code normally.

After confirming that the HelloWorld example is working, you can proceed to run the example for your device. The source file will be named the same as the software object for your device. If you are not sure what the software object for your device is, find your Phidget on our webpage, and then check the API documentation for it.

Once you have the C/C++ examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget C/C++ library. To begin:

1. Generate a new Visual C++: Win32 Console Application project with a descriptive name such as PhidgetTest.

2. Next, select Console Application.

3. Open the project properties window.

4. Navigate to Configuration Properties → C/C++.

5. Add "C:\Program Files\Phidgets" to the additional directories field. This step will find the phidget21.h file in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly.

6. Navigate to Configuration Properties → Linker → Input.

7. Edit the additional dependencies and add "C:\Program Files\Phidgets\phidget21.lib". This step will find the phidget21.lib file in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly.

8. The project now has access to the Phidget function calls and you are ready to begin coding.

Then, in your code, you will need to include the Phidget C/C++ library:

  #include <phidget21.h>

The same teaching section which describes the examples also has further resources for programming your Phidget.

Visual Studio 2003

Use Our Examples

1. Start by downloading the examples. You can import these examples into a Visual Studio 2003 C++ project. Afterwards, unpack them into a folder. Here, you can find example programs for all the devices. You will need this example source code to be copied into your C++ project later on. The easiest way to confirm that your environment is set up properly will be to compile and run the HelloWorld C/C++ example.

2. A new project will need to be created. Generate a new Visual C++ empty project(.NET) with a descriptive name such as HelloWorld.

3. Create a new C++ file by adding a new item to the source files folder.

4. An empty C++ file will pop up. Please copy and paste the contents of the HelloWorld.c program into here.

5. Next, the project setting needs to be set up. Open the project properties window.

6. Navigate to Configuration Properties → C/C++.

7. Add "C:\Program Files\Phidgets" to the additional include directories field. This step will find the phidget21.h file in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly.

8. Navigate to Configuration Properties → Linker → Input.

9. Add "C:\Program Files\Phidgets\phidget21.lib" to the additional dependencies field. This step will find the phidget21.lib file in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly.

10. Now, you can run the example. Click on Debug → Start Without Debugging.

11. This program will detect for devices that are attached/detached on the computer. Go ahead, and attach or detach your devices! Here is an example output:

After confirming that the HelloWorld example is working, you can proceed to run the example for your device. The source file will be named the same as the software object for your device. If you are not sure what the software object for your device is, find your Phidget on our webpage, and then check the API documentation for it.

Once you have the C/C++ examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget C/C++ library. Please see the Use Our Examples section for instructions.

Then, in your code, you will need to include the Phidget C/C++ library:

  #include <phidget21.h>

Visual Studio C++ 6.0

Use Our Examples

1. Download the examples and unpack them into a folder. Here, you can find example programs for all the devices. You will need this example source code to be copied into your C++ project later on. The easiest way to confirm that your environment is set up properly will be to compile and run the HelloWorld C/C++ example.

2. Next, a new project will need to be created. Generate a new Win32 Console Application project with a descriptive name such as HelloWorld.

3. Create an empty project.

4. Next, the project settings needs to be set up. Navigate to Project → Settings → C/C++ → Preprocessor.

5. Add C:\Program Files\Phidgets to the additional include directories field. This step will find the phidget21.h file in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly.

6. Navigate to Project → Settings → Link → Input → Additional library Path.

7. Add phidget21.lib to the object/library modules field.

8. Add C:\Program Files\Phidgets to the additional library path. This step will find the phidget21.lib file in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly.

The project now has access to the Phidget function calls and you are ready to begin coding.

To import the example program into your project, please:

9. Create a new C++ file by navigating to File → New → Files → C++ Source File and enter a descriptive name such as HelloWorld.

10. An empty C++ file will pop up. Please copy and paste the contents of the HelloWorld.c program here.

11. Now, you can run the example. Click on Build → Execute.

12. This program will detect for devices that are attached/detached on the computer. Go ahead, and attach or detach your devices! Here is an example output:

After confirming that the HelloWorld example is working, you can proceed to run the example for your device. The source file will be named the same as the software object for your device. If you are not sure what the software object for your device is, find your Phidget on our webpage, and then check the API documentation for it.

Once you have the C/C++ examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget C/C++ library. Please see the Use Our Examples section for instructions.

In your .c source code file, you must include a reference to the library header:

  #include <phidget21.h>

Then, you would compile your completed C/C++ code the same way as shown in the Use Our Examples section.

To learn how to write your own code for your Phidget, and to learn more about our API, we have a teaching section to help you follow the provided C/C++ examples and which has resources such as the API reference.

Borland

Use Our Examples

In addition to running one of the two Windows Installers above (which you probably already have if you worked through the Getting Started page for your device), you will need the Borland C++ Libraries. phidget21bcc.lib is typically placed in C:\Program Files\Phidgets, but you are free to place it in any directory you wish.

After installing the Phidget C/C++ library, you're ready to download the examples and run the examples.

Afterwards, unpack the examples. The easiest way to confirm that your environment is set up properly will be to compile and run the HelloWorld C/C++ example. Locate the HelloWorld.c file and type the following to compile the file and link the Phidget C/C++ library:

To compile, link the Phidget C/C++ library and build a binary executable, enter the following in a command line prompt in the directory with HelloWorld.c:

  bcc32 -eHelloWorld -I"C:\Program Files\Phidgets" -L"C:\Program Files\Phidgets" phidget21bcc.lib HelloWorld.c

It is assumed that phidget21bcc.lib and phidget21.h are placed in C:\Program Files\Phidgets. If the files are placed in another location, please adjust the paths to both of the file's location accordingly.

In this case, HelloWorld.c would be the .c file specific to your device. After using bcc32, you will have an executable named HelloWorld that you can run.

This program will detect for devices that are attached/detached on the computer. Go ahead, and attach or detach your devices! Here is an example output:

After confirming that the HelloWorld example is working, you can proceed to run the example for your device. The source file will be named the same as the software object for your device. If you are not sure what the software object for your device is, find your Phidget on our webpage, and then check the API documentation for it.

Write Your Own Code

When writing your code from scratch, you start it as you would any C/C++ code with Borland. In your .c source code file, you must include a reference to the library header:

  #include <phidget21.h>

Then, you would compile your completed C/C++ code the same way as the examples above.

To learn how to write your own code for your Phidget, and to learn more about our API, we have a teaching section to help you follow the provided C/C++ examples and which has resources such as the API reference.

GCC on Windows

Cygwin/MinGW

Use Our Examples

Download the examples and unpack them into a folder. Afterwards, unpack the examples. The easiest way to confirm that your environment is set up properly will be to compile and run the HelloWorld C/C++ example. Locate the HelloWorld.c file and type the following to compile the file and link the Phidget C/C++ library in a command line prompt:

Cygwin

  gcc example.c -o HelloWorld -I"/cygdrive/c/Program Files/Phidgets" -L"/cygdrive/c/Program Files/Phidgets" -lphidget21

MinGW

  gcc example.c -o HelloWorld -I"C:\Program Files\Phidgets" -L"C:\Program Files\Phidgets" -lphidget21

After using gcc, you will have an executable named HelloWorld that you can run. It is assumed that phidget21.h and phidget21.lib are placed in C:\Program Files\Phidgets. If the files are placed in another location, please adjust the paths to the file's location accordingly.

After using gcc, you will have an executable named HelloWorld that you can run.

This program will detect for devices that are attached/detached on the computer. Go ahead, and attach or detach your devices! Here is an example output:

After confirming that the HelloWorld example is working, you can proceed to run the example for your device. The source file will be named the same as the software object for your device. If you are not sure what the software object for your device is, find your Phidget on our webpage, and then check the API documentation for it.

Write Your Own Code

When writing your code from scratch, you start it as you would any C/C++ code with Cygwin/MinGW in your favourite text editor. In your .c source code file, you must include a reference to the library header:

  #include <phidget21.h>

Then, you would compile your completed C/C++ code the same way as shown in the Use Our Examples section above.

To learn how to write your own code for your Phidget, and to learn more about our API, we have a teaching section to help you follow the provided C/C++ examples and which has resources such as the API reference.

Dev C++

Use Our Examples

1. Download the examples and unpack them into a folder. Here, you can find example programs for all the devices. The source file will be named the same as the software object for your device. If you are not sure what the software object for your device is, find your Phidget on our webpage, and then check the API documentation for it. You will need this example source code to be copied into your Dev C++ project later on. The easiest way to confirm that your environment is set up properly will be to compile and run the HelloWorld C/C++ example.

2. In order to control Phidgets with Dev C++, we will use the reimp tool to convert the phidget21.lib to a format that Dev C++ accepts. Download the reimp tool. Reimp is part of MinGW, a minimal UNIX emulator for Windows, and it is specifically within the mingw-utils package. You can check MinGW's release notes to ensure Reimp is in the version you are using.

3. Open up command line and traverse to the directory containing the reimp tool. Type the following command to create libphidget21.a.

  reimp.exe "C:\Program Files\Phidgets\phidget21.lib"

The command above assumes that the phidget21.lib is in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly. Please note that the 64 bit version of phidget21.lib is not supported on Dev C/C++. Please use the 32 bit version of phidget21.lib.

4. Place libphidget21.a in <Dev-Cpp Install Directory>/lib.

5. Next, a new project will need to be created. Generate a new console application with a descriptive name such as PhidgetTest. Please select C as the project type.

6. Next, the project settings needs to be set up. Navigate to Project Options → Directories → Include Directories.

7. Add a new path to C:\Program Files\Phidgets. This step will find the phidget21.h file in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly.

8. Navigate to Project Options → Parameters → Linker.

9. Add -lphidget21 to the field. This step will find the libphidget21.a file in <Dev-Cpp Install Directory>/lib.

10. To import the HelloWorld program into your project, please open up main.c in the editor.

11. An empty C file will pop up. Please copy and paste the contents of the example program.

12. Now, you can run the example. Click on Execute → Compile & Run.

13. This program will detect for devices that are attached/detached on the computer. Go ahead, and attach or detach your devices! Here is an example output:

After confirming that the HelloWorld example is working, you can proceed to run the example for your device. The source file will be named the same as the software object for your device. If you are not sure what the software object for your device is, find your Phidget on our webpage, and then check the API documentation for it.

Once you have the C/C++ examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget C/C++ library. Please see the Use Our Examples section for instructions.

In your .c source code file, you must include a reference to the library header:

  #include <phidget21.h>

Then, you would compile your completed C/C++ code the same way as the examples above.

To learn how to write your own code for your Phidget, and to learn more about our API, we have a teaching section to help you follow the provided C/C++ examples and which has resources such as the API reference.

OS X

C/C++ has excellent support on OS X through the gcc compiler.

The first step in using C/C++ on Mac is to install the Phidget C/C++ library. Compile and install them as explained on the Getting Started guide for your device, which you can find in its user guide. Then, the OS - OS X page also describes the different Phidget files, their installed locations, and their roles.

Use Our Examples

After installing the main Phidget library for OS X as above, you're ready to download the examples. Afterwards, unzip the file. 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.

To compile, link the Phidget C/C++ library, and build an executable binary on OS X, do (for example, depending on the Headers location):

  gcc example.c -o example -framework Phidget21 -I/Library/Frameworks/Phidget21.framework/Headers

After using gcc, you will have an executable named example that you can run.

Write Your Own Code

When writing your code from scratch, you must include a reference to the library header:

  #include <phidget21.h>

Then, you would compile your completed C/C++ code the same way as shown in the Use Our Example section above.

To learn how to write your own code for your Phidget, and to learn more about our API, we have a teaching section to help you follow the provided C/C++ examples. Even more help and references are provided from there.

Linux

C/C++ has support on Linux through the gcc compiler.

The first step in using C/C++ on Linux is to install the Phidget libraries. Compile and install them as explained on the main Linux page. That Linux page also describes the different Phidget files, their installed locations, and their roles.

Use Our Examples

After installing the Phidget libraries for Linux as above, you're ready to download and run the examples:

• Generic C/C++ Examples

To run the example code, you'll need to download and unpack the examples, and then find the source code for your device. The source file will be named the same as the software object for your device. If you are not sure what the software object for your device is, find your Phidget on our webpage, and then check the API documentation for it. You can also use the HelloWorld program, which a basic program that can run with any Phidget. Then, compile the code under your platform and run it. When compiling, you need to link to the Phidget library.

To compile, link the Phidget libraries and build a binary executable on Linux, do the following in a terminal in the directory with example.c:

  gcc example.c -o example -lphidget21

In this case, example.c would be the .c file specific to your device. After using gcc, you will have an executable named example that you can run.

On Linux, if you have not set up your udev rules for USB access, you will need to run the program as root:

  sudo ./example

Write Your Own Code

When writing your code from scratch, you start it as you would any C/C++ code on Linux, such as within a text editor like Emacs, Vi, Gedit, or Kate. In your .c source code file, you must include a reference to the library header:

  #include <phidget21.h>

Then, you would compile your completed C/C++ code the same way as the examples above.

To learn how to write your own code for your Phidget, and to learn more about our API, we have a teaching section to help you follow the provided C/C++ examples and which has resources such as the API reference.

Windows CE

Description of Library Files

C/C++ programs on Windows CE depend on the following files, which the Windows CE installer puts onto your system:

• phidget21.dll contains the actual Phidget library, which is used at run-time. It is placed in \Windows.
• PhidgetWebService21.exe is used to control Phidgets remotely across a network using the PhidgetWebService. It can be placed anywhere on the system.
• phidget21.lib is used by your compiler to link to the dll. Your compiler has to know where this file is.
• phidget21.h lists all the Phidget API function calls available to your code. Your compiler also has to know where this file is.
• phidget.dll is the Phidgets kernel driver. It is placed in \Windows.

Visual Studio 2005/2008/2010

Use Our Examples

Currently, we have no example code for C/C++ on Windows CE. However, set up is very much the same as what it would be with Visual Studio 2005/2008/2010 in Windows. The phidget21.h and phidget21.lib can be downloaded here.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget C/C++ library. To begin:

1. Generate a new Visual C++: Win32 Smart Device project with a descriptive name such as PhidgetTest.

2. Select Next.

3. Select the SDK(s) that you want to code against and elect Next.

4. Create a console application and select Next.

3. Open the project properties window.

4. Navigate to Configuration Properties → C/C++.

5. Add "C:\Program Files\Phidgets" to the additional directories field. This step will find the phidget21.h file in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly.

6. Navigate to Configuration Properties → Linker → Input.

7. Edit the additional dependencies and add "C:\Program Files\Phidgets\phidget21.lib". This step will find the phidget21.lib file in the corresponding directory. If the file is placed in another location, please adjust the path to the file's location accordingly.

8. The project now has access to the Phidget function calls and you are ready to begin coding.

Then, in your code, you will need to include the Phidget C/C++ library:

  #include <phidget21.h>

The same teaching section which describes the examples also has further resources for programming your Phidget.

Follow the Examples

By following the instructions for your operating system and compiler above, you probably now have a working example and want to understand it better so you can change it to do what you want.

Your main reference for writing C code will be our C/C++ API information, with syntax for all of our functions:

Code Snippets

When programming in C/C++, you're in luck. All of our code snippet examples on our General Phidget Programming page are in both C++ and Java. Therefore, we do not include any here, because that page is much more in-depth, and you won't have to have two pages open at once. So head over there, and start writing code!

Common Problems and Solutions/Workarounds

Issue: I am using a non US-English version of Windows, and the Visual C/C++ examples run into a linker error

Affected Operating Systems: Windows

The example projects, by default finds the phidget21.h and phidget21.lib in ${SystemDrive}\Program Files\Phidgets. If you are using a non US-English version of Windows, the Phidget drivers may be installed into a different location. To resolve, you will have to modify the paths to these two files. For instructions, please see your environment/compiler section.