Language - C: Difference between revisions

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Preamble about the language and its general strengths and weaknesses.
__NOTOC__
[[Category:Language]]
We provide support for the C language in all major operating systems. We also provide instructions on how to get your project started in a number of common development environments. Select your operating system and preferred development environment below, and follow the instructions to get your project running with Phidgets.


==Assessment for use with Phidgets==
If you do not know which development environment you want to use, or your development environment of choice is not listed, we recommend starting with GCC as the simplest path to getting your code running.
Our honest opinion on how well this language is suited to controlling Phidgets. If it is a poor choice, suggest and link similar (better) languages.


==Support==
Once you have set up your development environment to run with Phidgets, we recommend you follow our guide on [[Phidget Programming Basics]]. The guide will showcase the fundamentals of programming with Phidgets, with examples in C.
We provide [[Levels of Support|full support]] to C and C++.


==Restrictions==
==Choose Your Development Environment:==
In this section, list any restrictions or limitations that this particular language may impose. For example, incompatibility with certain operating systems.


==Development Environments and Compilers==
{{Language_-_C_Dev_Environment_Table}}


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.
== Quick Downloads ==


==Drivers, Libraries and Resources==
If you already know what you're doing and just need the files, you can find them all below.
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:
* [http://www.phidgets.com/drivers.php Phidget Framework]
You will need the Phidget Framework to use and to program with Phidgets. We also recommend that you download the following reference materials:
* [http://www.phidgets.com/documentation/Phidget21_C_Doc.zip API Manual]
* [http://www.phidgets.com/documentation/web/cdoc/index.html API Reference]
* Sample Code:
**[http://www.phidgets.com/downloads/examples/VCpp_2.1.8.20110615.zip Windows]
**[http://www.phidgets.com/downloads/examples/phidget21-c-examples_2.1.8.20110615.tar.gz Linux/MacOS]
* Phidget21 Library:
**[http://www.phidgets.com/downloads/libraries/phidget21-x86_2.1.8.20110615.zip x86]
**[http://www.phidgets.com/downloads/libraries/phidget21-x64_2.1.8.20110615.zip x64]
**[http://www.phidgets.com/downloads/libraries/phidget21bcc_2.1.8.20110615.zip Borland C++]
* You can find a high level discussion about programming with Phidgets in general on the [[General API]] page.
* The [[Device Functionality]] page explains the general operational information for your device.  


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


==Getting Started (Windows)==
*{{Phidget22API}}  (select C from the drop-down menu)


The Phidget examples were written using Visual C++ 2005 and this tutorial assumes its use.
=== Example Code ===
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.
*{{SampleCode|C|C Examples}}
* 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.
===Libraries===


===Coding For Your Phidget===
{{AllQuickDownloads}}
 
Before you can use the Phidget, you must include a reference to the library header.
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  #include "phidget21.h"
 
</source>
</font>
</div>
 
Afterwards, the Phidget object will need to be declared and then initialized.
For example, we can declare a PhidgetInterfaceKit inside our main function with:
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  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;
  }
 
</source>
</font>
</div>
 
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.
 
===Connecting to the Phidget===
 
Next, the program needs to try and connect to the Phidget through an open call.
The open will tell the program to continuously try to connect to a Phidget, based on the parameters given, even trying to reconnect if it gets disconnected.
This means that simply calling open does not guarantee you can use the Phidget immediately.
We can handle this by using event driven programming and tracking the AttachEvents and DetachEvents, or by calling waitForAttachment.
WaitForAttachment will block indefinitely until a connection is made to the Phidget, or an optional timeout is exceeded.
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  CPhidget_open((CPhidgetHandle)ifKit, -1);
  CPhidget_waitForAttachment((CPhidgetHandle)ifKit, 2500);
 
</source>
</font>
</div>
 
The different types of open can be used with parameters to try and get the first device it can find, open based on its serial number, or even open across the network.
The API manual lists all of the available modes that open provides.
One important thing to remember is that when working with Phidgets, a local connection will reserve the device until closed.
This prevents any other instances from retrieving data from the Phidget, including other programs.
The one connection per device limit does not apply when exclusively using the Phidget Webservice.
At the end of your program, don’t forget to call close to free any locks on the Phidget.
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  CPhidget_close((CPhidgetHandle)ifKit);
  CPhidget_delete((CPhidgetHandle)ifKit);
 
</source>
</font>
</div>
 
===Event Driven Programming===
 
We recommend the use of event driven programming when working with Phidgets.
In C/C++, we hook an event handler with the following code: 
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  CPhidgetInterfaceKit_set_OnSensorChange_Handler (ifKit, SensorChangeHandler, NULL);
  int __stdcall SensorChangeHandler(CPhidgetInterfaceKitHandle IFK, void *usrptr, int Index, int Value)
  {
      printf("Sensor: %d > Value: %d\n", Index, Value);
      //Insert your code hereGetting_Started_VisualC created: 02/27/09 Page 3
      return 0;
  }
 
</source>
</font>
</div>
 
With this function, the code inside SensorChangedHandler will get executed every time the InterfaceKit reports a change on one of its analog inputs.
Some events such as Attach and Detach belong to the base Phidget object and thus are common to all types of Phidgets.
Please refer to the API manual for a full list of events and their usage.
 
===Working directly with the Phidget===
 
Some values can be read and sent directly to the Phidget.
Simply use the C API functions such as CPhidgetInterfaceKit_getSensorValue() or CPhidgetInterfaceKit_setOutState() for InterfaceKits.
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  int val;
  for (int i = 0; i < 10; i++) {
    CPhidgetInterfaceKit_getSensorValue(phid, 0, &val);
    printf("Value: %d\n", val);
  }
 
</source>
</font>
</div>
 
The functions can be used inside a polling loop as an alternative to event driven programming.
Above, a sensor attached to the PhidgetInterfaceKit is read and its value is displayed to screen.
 
===Working with multiple Phidgets===
 
Multiple Phidgets of the same type can easily be run inside the same program.
In our case, it  requires another PhidgetInterfaceKit instance to be defined and initialized.
The new instance can then be set up, opened and used in the same process as the previous one.
If the application needs to distinguish between the devices, open can be called with the serial number of a specific Phidget.
 
===Other Phidgets===
 
The design given in this document can also be followed for almost all Phidgets.
For example, if you were using a PhidgetRFID instead of an Interfacekit, you would call CPhidgetRFID_create instead of CPhidgetInterfaceKit_create.
The functions and events available would change but they can be accessed in a similar manner.
 
==Getting Started (MacOS/Linux)==
 
===Coding For Your Phidget===
 
Before you can use the Phidget, you must include a reference to the library header.
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  #include <phidget21.h>
 
</source>
</font>
</div>
 
Afterwards, the Phidget object will need to be declared and then initialized. For example, we can declare a PhidgetInterfaceKit inside our main function with:
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  int main(int argc, char* argv[])
  {
    CPhidgetInterfaceKitHandle ifKit = 0;
    CPhidgetInterfaceKit_create(&ifKit);
    //More code goes here
    return 0;
  }
 
</source>
</font>
</div>
 
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.
 
===Connecting to the Phidget===
 
Next, the program needs to try and connect to the Phidget through an open call.
The open will tell the program to continuously try to connect to a Phidget, based on the parameters given, even trying to reconnect if it gets disconnected.
This means that simply calling open does not guarantee you can use the Phidget immediately.
We can handle this by using event driven programming and tracking the AttachEvents and DetachEvents, or by calling waitForAttachment.
WaitForAttachment will block indefinitely until a connection is made to the Phidget, or an optional timeout is exceeded.
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  CPhidget_open((CPhidgetHandle)ifKit, -1);
  CPhidget_waitForAttachment((CPhidgetHandle)ifKit, 10000);
 
</source>
</font>
</div>
 
The different types of open can be used with parameters to try and get the first device it can find, open based on its serial number, or even open across the network.
The API manual lists all of the available modes that open provides.
One important thing to remember is that when working with Phidgets, a local connection will reserve the device until closed.
This prevents any other instances from retrieving data from the Phidget, including other programs.
The one connection per device limit does not apply when exclusively using the Phidget Webservice.
At the end of your program, don’t forget to call close to free any locks on the Phidget.
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  CPhidget_close((CPhidgetHandle)ifKit);
  CPhidget_delete((CPhidgetHandle)ifKit);
 
</source>
</font>
</div>
 
===Event Driven Programming===
 
We recommend the use of event driven programming when working with Phidgets. In C/C++, we hook an event handler with the following code: 
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  CPhidgetInterfaceKit_set_OnSensorChange_Handler (ifKit, SensorChangeHandler, NULL);
  int SensorChangeHandler(CPhidgetInterfaceKitHandle IFK, void *usrptr, int
  Index, int Value)
  {
    printf("Sensor: %d > Value: %d\n", Index, Value);
    return 0;
  }
 
</source>
</font>
</div>
 
With this function, the code inside SensorChangedHandler will get executed every time the InterfaceKit reports a change on one of its analog inputs.
Some events such as Attach and Detach belong to the base Phidget object and thus are common to all types of Phidgets.
Please refer to the API manual for a full list of events and their usage.
 
===Working directly with the Phidget===
 
Some values can be read and sent directly to the Phidget. Simply use the C API functions such as CPhidgetInterfaceKit_getSensorValue() or CPhidgetInterfaceKit_setOutState() for InterfaceKits.
 
<div style="background-color: #f3f3f3; border-color: #1c9edb; border-width:1px; border-style: dashed;">
<font size="3">
<source lang=cpp>
 
  int val;
  for (int i = 0; i < 10; i++) {
    CPhidgetInterfaceKit_getSensorValue(phid, 0, &val);
    printf("Value: %d\n", val);
  }
 
</source>
</font>
</div>
 
The functions can be used inside a polling loop as an alternative to event driven programming.
Above, a sensor attached to the PhidgetInterfaceKit is read and its value is displayed to screen.
 
===Working with multiple Phidgets===
 
Multiple Phidgets of the same type can easily be run inside the same program. In our case, it requires another PhidgetInterfaceKit instance to be defined and initialized.
The new instance can then be set up, opened and used in the same process as the previous one.
If the application needs to distinguish between the devices, open can be called with the serial number of a specific Phidget.
 
===Other Phidgets===
 
The design given in this document can also be followed for almost all Phidgets.
For example, if you were using a PhidgetRFID instead of an Interfacekit, you would call CPhidgetRFID_create instead of CPhidgetInterfaceKit_create.
The functions and events available would change but they can be accessed in a similar manner.
 
===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.

Revision as of 22:13, 28 February 2019

We provide support for the C language in all major operating systems. We also provide instructions on how to get your project started in a number of common development environments. Select your operating system and preferred development environment below, and follow the instructions to get your project running with Phidgets.

If you do not know which development environment you want to use, or your development environment of choice is not listed, we recommend starting with GCC as the simplest path to getting your code running.

Once you have set up your development environment to run with Phidgets, we recommend you follow our guide on Phidget Programming Basics. The guide will showcase the fundamentals of programming with Phidgets, with examples in C.

Choose Your Development Environment:

C Development Environments
OS - Windows Windows

C VS WIN.png C VS WIN on.png

C GCC WIN.png C GCC WIN on.png

C CB WIN.png C CB WIN on.png

OS - macOS macOS

C GCC MAC.png C GCC MAC on.png

OS - Linux Linux

C GCC LNX.png C GCC LNX on.png

OS - Linux Phidget SBC Linux

C GCC SBC.png C GCC SBC on.png

Quick Downloads

If you already know what you're doing and just need the files, you can find them all below.

Documentation

Example Code

Libraries

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