exampleHelper.h

The exampleHelper header offers some useful functions for

- device and
- property handling

and is used in nearly all examples.

Program location

The source file exampleHelper.h can be found under:

%INSTALLDIR%\apps\Common\

Note

If you have installed the package without example applications, this file will not be available. On Windows® the sample application can be installed or removed from the target system at any time by simply restarting the installation package.

What the header file offers

The header file offers following functions for device handling like

• getDeviceFromUserInput()
• getValidDevices()
• manuallyStartAcquisitionIfNeeded(), manuallyStopAcquisitionIfNeeded()
  These functions will call the underlying start/stop SDK function only when needed thus when the mvIMPACT::acquire::Device::acquisitionStartStopBehaviour property has been set to mvIMPACT::acquire::assbUser.

for property handling like:

• DisplayPropertyDictionary()
• conditionalSetProperty(), conditionalSetEnumPropertyByString()
  These functions set an enumerated property to a certain value if this value is supported by the property.
• displayPropertyData()
  This function will display some more information about the current property like the current value, possible min. and max. values etc.
• displayPropertyDataWithValidation()
  This function will check if the property is valid and afterwards the function will display some more information about the current property like the current value, possible min. and max. values etc.
• modifyPropertyValue()
  This function will save the property value.
• displayAndModifyPropertyDataWithValidation()
  This function combines the functions displayPropertyDataWithValidation() and modifyPropertyValue().
• match()
  This function allows a tolerant string compare.
• supportsEnumStringValue()
  This function checks if a certain string would be an accepted value for a property.
• supportsValue()
  This function checks if a certain value would be an accepted value for a property by validating the value against potential translation dictionaries as well as limits.

The property handling functions use at a basic level the read and write functions:

• read()
• readS() for strings

  std::cout << "Property '" << prop.name() << "' set to '" << prop.readS() << "'." << std::endl;

• write()
• writeS() for strings

  prop.writeS( val, valIndex );

and for some input handling:

• waitForInput()
  This function checks for changes reported by a certain file descriptor and then returns.
• checkKeyboardInput()
  This function checks if a key has been pressed since the last time this function has been called.

In addition to the device handling related functionalities there is a specific function to check the payload type of a received mvIMPACT::acquire::Request object:

• handleAdvancedPayloadType()

Source code

/*
 * @description: Example applications for Impact Acquire
 * @copyright: Copyright (C) 2009 - 2024 Balluff GmbH
 * @authors: APIs and drivers development team at Balluff GmbH
 * @initial date: 2009-02-25
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next paragraph) shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
//-----------------------------------------------------------------------------
#ifndef exampleHelperH
#define exampleHelperH exampleHelperH
//-----------------------------------------------------------------------------
#include <algorithm>    // IWYU pragma: export
#include <iostream>     // IWYU pragma: export
#include <set>          // IWYU pragma: export
#include <string>       // IWYU pragma: export
 
#include <common/designData.h>  // IWYU pragma: export
#include <mvIMPACT_CPP/mvIMPACT_acquire.h>  // IWYU pragma: export
 
//-----------------------------------------------------------------------------
template<class _Ty>
class DisplayDictEntry
//-----------------------------------------------------------------------------
{
public:
    void operator()( const std::pair<std::string, _Ty>& data ) const
    {
        std::cout << "  [" << data.second << "]: " << data.first << std::endl;
    }
};
 
//-----------------------------------------------------------------------------
class DisplayComponent
//-----------------------------------------------------------------------------
{
public:
    void operator()( const Component& data ) const
    {
        if( data.isValid() )
        {
            std::cout << "  " << data.name() << "(" << data.typeAsString() << ")" << std::endl;
        }
    }
};
 
//-----------------------------------------------------------------------------
class DisplayProperty
//-----------------------------------------------------------------------------
{
public:
    void operator()( const std::pair<std::string, mvIMPACT::acquire::Property>& data ) const
    {
        if( data.second.isValid() )
        {
            std::cout << data.first << ": " << data.second.readSArray() << "(" << data.second.flagsAsString() << ")" << std::endl;
        }
    }
};
 
//-----------------------------------------------------------------------------
template<class _Ty>
void DisplayPropertyDictionary( const mvIMPACT::acquire::Property& p )
//-----------------------------------------------------------------------------
{
    _Ty prop( p );
#if defined(_MSC_VER) && (_MSC_VER < 1300) // is 'old' VC 6 Microsoft compiler?
    std::vector<std::pair<std::string, _Ty::value_type> > dict;
    prop.getTranslationDict( dict );
    std::for_each( dict.begin(), dict.end(), DisplayDictEntry<_Ty::value_type>() );
#else
    std::vector<std::pair<std::string, typename _Ty::value_type> > dict;
    prop.getTranslationDict( dict );
    std::for_each( dict.begin(), dict.end(), DisplayDictEntry<typename _Ty::value_type>() );
#endif // #ifdef _MSC_VER
}
 
//-----------------------------------------------------------------------------
/// \brief Checks is a certain value for property is supported.
template<class _Tx>
bool supportsEnumStringValue( const _Tx& prop, const std::string& value )
//-----------------------------------------------------------------------------
{
    if( prop.hasDict() )
    {
        typename std::vector<std::string> sequence;
        prop.getTranslationDictStrings( sequence );
        return std::find( sequence.begin(), sequence.end(), value ) != sequence.end();
    }
    return false;
}
 
//-----------------------------------------------------------------------------
/// \brief Checks is a certain value for property is supported.
template<class _Tx, typename _Ty>
bool supportsValue( const _Tx& prop, const _Ty& value )
//-----------------------------------------------------------------------------
{
    if( prop.hasDict() )
    {
        typename std::vector<_Ty> sequence;
        prop.getTranslationDictValues( sequence );
        return std::find( sequence.begin(), sequence.end(), value ) != sequence.end();
    }
 
    if( prop.hasMinValue() && ( prop.getMinValue() > value ) )
    {
        return false;
    }
 
    if( prop.hasMaxValue() && ( prop.getMaxValue() < value ) )
    {
        return false;
    }
 
    return true;
}
 
//-----------------------------------------------------------------------------
/// \brief Sets a property to a certain value if this value is supported.
template<typename _Ty, typename _Tx>
void conditionalSetProperty( const _Ty& prop, const _Tx& value, bool boSilent = false )
//-----------------------------------------------------------------------------
{
    if( prop.isValid() && prop.isWriteable() && supportsValue( prop, value ) )
    {
        prop.write( value );
        if( !boSilent )
        {
            std::cout << "Property '" << prop.name() << "' set to '" << prop.readS() << "'." << std::endl;
        }
    }
}
 
//-----------------------------------------------------------------------------
/// \brief Sets a property to a certain value if this value is supported.
template<typename _Ty>
void conditionalSetEnumPropertyByString( const _Ty& prop, const std::string& value, bool boSilent = false )
//-----------------------------------------------------------------------------
{
    if( prop.isValid() && prop.isWriteable() && supportsEnumStringValue( prop, value ) )
    {
        prop.writeS( value );
        if( !boSilent )
        {
            std::cout << "Property '" << prop.name() << "' set to '" << prop.readS() << "'." << std::endl;
        }
    }
}
 
//-----------------------------------------------------------------------------
/// This function makes heavy use of strings. In real world applications
/// this can be avoided if optimal performance is crucial. All properties can be modified
/// via strings, but most properties can also be modified with numerical (int / double )
/// values, which is much faster, but not as descriptive for a sample application
inline void displayPropertyData( const mvIMPACT::acquire::Property& prop )
//-----------------------------------------------------------------------------
{
    const std::string name( prop.name() );
    std::cout << std::endl
              << "Property '" << name << "'(display name: '" << prop.displayName() << "', type: " << prop.typeAsString() << ") currently specifies the following flags: " << prop.flagsAsString() << std::endl
              << std::endl;
    const std::string doc( prop.docString() );
    if( !doc.empty() )
    {
        std::cout << "The following documentation has been reported by the driver for this feature: " << std::endl
                  << doc << std::endl
                  << std::endl;
    }
    if( prop.selectedFeatureCount() > 0 )
    {
        std::vector<Component> selectedFeatureList;
        prop.selectedFeatures( selectedFeatureList );
        std::cout << "The following features are selected by this feature(Whenever the current feature is modified, all selected features might change):" << std::endl;
        std::for_each( selectedFeatureList.begin(), selectedFeatureList.end(), DisplayComponent() );
        std::cout << std::endl;
    }
    if( prop.selectingFeatureCount() > 0 )
    {
        std::vector<Component> selectingFeatureList;
        prop.selectingFeatures( selectingFeatureList );
        std::cout << "The following features select this feature(Whenever a selecting features is modified, a selected one might change):" << std::endl;
        std::for_each( selectingFeatureList.begin(), selectingFeatureList.end(), DisplayComponent() );
        std::cout << std::endl;
    }
    if( prop.hasMinValue() )
    {
        std::cout << "The minimum value of '" << name << "' is " << prop.readS( mvIMPACT::acquire::plMinValue ) << std::endl;
    }
    if( prop.hasMaxValue() )
    {
        std::cout << "The maximum value of '" << name << "' is " << prop.readS( mvIMPACT::acquire::plMaxValue ) << std::endl;
    }
    if( prop.hasStepWidth() )
    {
        std::cout << "The increment of '" << name << "' is " << prop.readS( mvIMPACT::acquire::plStepWidth ) << std::endl;
    }
    if( prop.hasDict() )
    {
        std::cout << "'" << name << "' defines a dictionary. Valid values are: " << std::endl;
        mvIMPACT::acquire::TComponentType type = prop.type();
        if( type == mvIMPACT::acquire::ctPropInt )
        {
            DisplayPropertyDictionary<mvIMPACT::acquire::PropertyI>( prop );
        }
        else if( type == mvIMPACT::acquire::ctPropInt64 )
        {
            DisplayPropertyDictionary<mvIMPACT::acquire::PropertyI64>( prop );
        }
        else if( type == mvIMPACT::acquire::ctPropFloat )
        {
            DisplayPropertyDictionary<mvIMPACT::acquire::PropertyF>( prop );
        }
        else
        {
            std::cout << "Error! Unhandled enum prop type: " << prop.typeAsString() << std::endl;
        }
    }
    std::cout << "The current value of '" << name << "' is: '" << prop.readS() << "'" << std::endl;
}
 
//-----------------------------------------------------------------------------
inline bool displayPropertyDataWithValidation( const mvIMPACT::acquire::Property& prop, const std::string& name )
//-----------------------------------------------------------------------------
{
    if( !prop.isValid() )
    {
        std::cout << "Property '" << name << "' is not supported/available." << std::endl;
        return false;
    }
    displayPropertyData( prop );
    return true;
}
 
//-----------------------------------------------------------------------------
// Start the acquisition manually if this was requested(this is to prepare the driver for data capture and tell the device to start streaming data)
inline void manuallyStartAcquisitionIfNeeded( mvIMPACT::acquire::Device* pDev, const mvIMPACT::acquire::FunctionInterface& fi )
//-----------------------------------------------------------------------------
{
    if( pDev->acquisitionStartStopBehaviour.read() == mvIMPACT::acquire::assbUser )
    {
        const mvIMPACT::acquire::TDMR_ERROR result = static_cast<mvIMPACT::acquire::TDMR_ERROR>( fi.acquisitionStart() );
        if( result != mvIMPACT::acquire::DMR_NO_ERROR )
        {
            std::cout << "'FunctionInterface.acquisitionStart' returned with an unexpected result: " << result
                      << "(" << mvIMPACT::acquire::ImpactAcquireException::getErrorCodeAsString( result ) << ")" << std::endl;
        }
    }
}
 
//-----------------------------------------------------------------------------
// Stop the acquisition manually if this was requested
inline void manuallyStopAcquisitionIfNeeded( mvIMPACT::acquire::Device* pDev, const mvIMPACT::acquire::FunctionInterface& fi )
//-----------------------------------------------------------------------------
{
    if( pDev->acquisitionStartStopBehaviour.read() == mvIMPACT::acquire::assbUser )
    {
        const mvIMPACT::acquire::TDMR_ERROR result = static_cast<mvIMPACT::acquire::TDMR_ERROR>( fi.acquisitionStop() );
        if( result != mvIMPACT::acquire::DMR_NO_ERROR )
        {
            std::cout << "'FunctionInterface.acquisitionStop' returned with an unexpected result: " << result
                      << "(" << mvIMPACT::acquire::ImpactAcquireException::getErrorCodeAsString( result ) << ")" << std::endl;
        }
    }
}
 
//-----------------------------------------------------------------------------
/// This function makes heavy use of strings. In real world applications
/// this can be avoided if optimal performance is crucial. All properties can be modified
/// via strings, but most properties can also be modified with numerical (int / double )
/// values, which is much faster, but not as descriptive for a sample application
inline void modifyPropertyValue( const mvIMPACT::acquire::Property& prop, const std::string& param = "", const std::string& index = "" )
//-----------------------------------------------------------------------------
{
    try
    {
        const std::string name( prop.name() );
        if( prop.isWriteable() )
        {
            int valIndex = 0;
            if( param.empty() )
            {
                std::cout << "Enter the new value for '" << name << "': ";
                std::string val;
                std::cin >> val;
                // remove the '\n' from the stream
                std::cin.get();
                if( prop.valCount() > 1 )
                {
                    std::cout << "'" << name << "' defines " << prop.valCount() << " values. Enter the index (zero-based) of the value to modify: ";
                    std::cin >> valIndex;
                    // remove the '\n' from the stream
                    std::cin.get();
                }
                prop.writeS( val, valIndex );
            }
            else
            {
                if( !index.empty() )
                {
                    valIndex = atoi( index.c_str() );
                }
                prop.writeS( param, valIndex );
            }
        }
        else
        {
            std::cout << "'" << name << "' is read-only, thus can't be modified." << std::endl;
        }
    }
    catch( const mvIMPACT::acquire::ImpactAcquireException& e )
    {
        std::cout << "An exception occurred: " << e.getErrorString() << "(error code: " << e.getErrorCodeAsString() << ")" << std::endl;
    }
}
 
//-----------------------------------------------------------------------------
inline void displayAndModifyPropertyDataWithValidation( const mvIMPACT::acquire::Property& prop, const std::string& name )
//-----------------------------------------------------------------------------
{
    if( displayPropertyDataWithValidation( prop, name ) )
    {
        modifyPropertyValue( prop );
    }
    std::cout << std::endl;
}
 
//-----------------------------------------------------------------------------
inline ImageBuffer* handleAdvancedPayloadType( const mvIMPACT::acquire::Request* pRequest, const TPayloadType payloadType )
//-----------------------------------------------------------------------------
{
    ImageBuffer* pImageBuffer = 0;
    const std::string bufferTypeAsString( pRequest->payloadType.readS() );
    switch( payloadType )
    {
    case ptGenDC:
    case ptMultiPart:
        {
            const unsigned int bufferPartCount( pRequest->getBufferPartCount() );
            std::cout << "Buffer of type '" << bufferTypeAsString << "' captured, containing " << bufferPartCount << " part" << ( ( bufferPartCount > 1 ) ? "s (just the first one will be displayed)" : "" ) << std::endl;
            for( unsigned int i = 0; i < bufferPartCount; i++ )
            {
#ifndef __clang_analyzer__ // The analyzer does not understand the reference counting implemented in the ImageBufferDesc class thus incorrectly assumes an access to released memory here :-(
                const ImageBuffer* pPart = pRequest->getBufferPart( i ).getImageBufferDesc().getBuffer();
#endif // #ifndef __clang_analyzer__
                const TBufferPartDataType partType = pRequest->getBufferPart( i ).dataType.read();
                std::cout << "   Part " << i << " contains data of type: '" << pRequest->getBufferPart( i ).dataType.readS() << "' - " << pPart->iWidth << "x" << pPart->iHeight << " pixels @ " << pPart->iBytesPerPixel << " bytes per pixel";
                if( ( ( partType == bpdtGDC_2DImage ) || ( partType == bpdt2DImage ) ) && !pImageBuffer )
                {
                    pImageBuffer = pRequest->getBufferPart( 0 ).getImageBufferDesc().getBuffer();
                }
                std::cout << std::endl;
            }
        }
        break;
    case pt2DImage:
        // This is not an advanced data type and will probably be handled by the caller of this function. At least it is not our concern here!
        break;
    case ptH264:
    case ptChunkOnly:
    case ptJPEG:
    case ptJPEG2000:
    case ptUnknown:
    default:
        std::cout << "Buffer of type '" << bufferTypeAsString << "' with " << pRequest->bufferSizeFilled.read() << " bytes captured but its data type can not be displayed within this example." << std::endl;
        break;
    }
    return pImageBuffer;
}
 
//-----------------------------------------------------------------------------
inline std::ostream& operator<<( std::ostream& out, const mvIMPACT::acquire::Property& prop )
//-----------------------------------------------------------------------------
{
    out << prop.name() << ": " << prop.readS();
    return out;
}
 
//-----------------------------------------------------------------------------
/// \brief Allows string comparison with a defined character to ignore
/**
 *  This function allows a tolerant string compare. If \a candidate ends with \a wildcard
 *  \a candidate can be shorter then \a searchString as the rest of the string will be
 *  ignored. This is a helper function used internally by <b>DeviceManager</b> objects.
 *
 *  Examples:
 *
 * \code
 *  wildcard = '*'
 *  s1 = "blablabla"
 *  match( s1, "bl*bl*bla", '*' ); // will return 0
 *  // will return 0 ('*' is the default value for parameter 3 )
 *  match( s1, "bl*" );
 *  // the next call will return -1 as the first character MUST
 *  // be either a 'b' or the wildcard character.
 *  match( s1, "a*" );
 * \endcode
 *  \return
 *  - 0 if successful
 *  - -1 otherwise
 */
template<class _Elem, class _Traits, class _Ax>
int match( const std::basic_string<_Elem, _Traits, _Ax>& searchString, const std::basic_string<_Elem, _Traits, _Ax>& candidate, _Elem wildcard )
//-----------------------------------------------------------------------------
{
    typename std::basic_string<_Elem, _Traits, _Ax>::size_type searchLength = searchString.length();
    // determine search length
    if( candidate.length() < searchString.length() )
    {
        if( candidate.empty() )
        {
            return -1;
        }
 
        if( candidate[candidate.length() - 1] != wildcard )
        {
            return -1;
        }
        searchLength = candidate.length() - 1;
    }
    // search
    for( typename std::basic_string<_Elem, _Traits, _Ax>::size_type i = 0; i < searchLength; i++ )
    {
        if( ( candidate[i] != searchString[i] ) && ( candidate[i] != wildcard ) )
        {
            return -1;
        }
    }
    return 0;
}
 
typedef bool( *SUPPORTED_DEVICE_CHECK )( const mvIMPACT::acquire::Device* const );
 
//-----------------------------------------------------------------------------
inline mvIMPACT::acquire::Device* getDeviceFromUserInput( const mvIMPACT::acquire::DeviceManager& devMgr, SUPPORTED_DEVICE_CHECK pSupportedDeviceCheckFn = 0, bool boSilent = false, bool boAutomaticallyUseGenICamInterface = true )
//-----------------------------------------------------------------------------
{
    const unsigned int devCnt = devMgr.deviceCount();
    if( devCnt == 0 )
    {
        std::cout << "No compliant device found!" << std::endl;
        return 0;
    }
 
    std::set<unsigned int> validDeviceNumbers;
 
    // display every device detected that matches
    for( unsigned int i = 0; i < devCnt; i++ )
    {
        Device* pDev = devMgr[i];
        if( pDev )
        {
            if( !pSupportedDeviceCheckFn || pSupportedDeviceCheckFn( pDev ) )
            {
                std::cout << "[" << i << "]: " << pDev->serial.read() << " (" << pDev->product.read() << ", " << pDev->family.read();
                if( pDev->interfaceLayout.isValid() )
                {
                    if( boAutomaticallyUseGenICamInterface )
                    {
                        // if this device offers the 'GenICam' interface switch it on, as this will
                        // allow are better control over GenICam compliant devices
                        conditionalSetProperty( pDev->interfaceLayout, dilGenICam, true );
                    }
                    std::cout << ", interface layout: " << pDev->interfaceLayout.readS();
                }
                if( pDev->acquisitionStartStopBehaviour.isValid() )
                {
                    // if this device offers a user defined acquisition start/stop behaviour
                    // enable it as this allows finer control about the streaming behaviour
                    conditionalSetProperty( pDev->acquisitionStartStopBehaviour, assbUser, true );
                    std::cout << ", acquisition start/stop behaviour: " << pDev->acquisitionStartStopBehaviour.readS();
                }
                if( pDev->interfaceLayout.isValid() && !pDev->interfaceLayout.isWriteable() && pDev->isInUse() )
                {
                    std::cout << ", !!!ALREADY IN USE!!!";
                }
                std::cout << ")" << std::endl;
                validDeviceNumbers.insert( i );
            }
        }
    }
 
    if( validDeviceNumbers.empty() )
    {
        std::cout << devMgr.deviceCount() << " devices have been detected:" << std::endl;
        for( unsigned int i = 0; i < devCnt; i++ )
        {
            Device* pDev = devMgr[i];
            if( pDev )
            {
                std::cout << "  [" << i << "]: " << pDev->serial.read() << " (" << pDev->product.read() << ", " << pDev->family.read() << ")" << std::endl;
            }
        }
        std::cout << "However none of these devices seems to be supported by this sample." << std::endl << std::endl;
        return 0;
    }
 
    // get user input
    std::cout << std::endl << "Please enter the number in front of the listed device followed by [ENTER] to open it: ";
    unsigned int devNr = 0;
    std::cin >> devNr;
    // remove the '\n' from the stream
    std::cin.get();
 
    if( validDeviceNumbers.find( devNr ) == validDeviceNumbers.end() )
    {
        std::cout << "Invalid selection!" << std::endl;
        return 0;
    }
 
    if( !boSilent )
    {
        std::cout << "Using device number " << devNr << "." << std::endl;
    }
    return devMgr[devNr];
}
 
//-----------------------------------------------------------------------------
inline std::vector<mvIMPACT::acquire::Device*>::size_type getValidDevices( const mvIMPACT::acquire::DeviceManager& devMgr, std::vector<mvIMPACT::acquire::Device*>& v, SUPPORTED_DEVICE_CHECK pSupportedDeviceCheckFn = 0 )
//-----------------------------------------------------------------------------
{
    const unsigned int devCnt = devMgr.deviceCount();
    // display every device detected that matches
    for( unsigned int i = 0; i < devCnt; i++ )
    {
        Device* pDev = devMgr[i];
        if( pDev )
        {
            if( !pSupportedDeviceCheckFn || pSupportedDeviceCheckFn( pDev ) )
            {
                v.push_back( pDev );
            }
        }
    }
    return v.size();
}
 
#if defined(linux) || defined(__linux) || defined(__linux__) || defined(__APPLE__)
#   include <fcntl.h>
#   include <stdio.h>
#   include <sys/types.h>
#   include <termios.h>
#   include <unistd.h>
//-----------------------------------------------------------------------------
/// \brief Checks if something was written to a certain file descriptor
/** \return
 *  - 0 if timeout did elapse
 *  - 1 otherwise
 */
inline unsigned waitForInput( int maxWait_sec, int fd )
//-----------------------------------------------------------------------------
{
    fd_set rfds;
    struct timeval tv;
 
    FD_ZERO( &rfds );
#ifndef __clang_analyzer__ // See https://bugs.llvm.org/show_bug.cgi?id=8920
    FD_SET( fd, &rfds );
#endif // #ifndef __clang_analyzer__
 
    tv.tv_sec = maxWait_sec;
    tv.tv_usec = 0;
 
    return select( fd + 1, &rfds, NULL, NULL, &tv );
}
 
//-----------------------------------------------------------------------------
/** \return
 *  - 1 if a key has been pressed since the last call to this function
 *  - 0 otherwise
 */
inline int checkKeyboardInput( void )
//-----------------------------------------------------------------------------
{
    struct termios oldt, newt;
    tcgetattr( STDIN_FILENO, &oldt );
    newt = oldt;
    newt.c_lflag &= ~( ICANON | ECHO );
    tcsetattr( STDIN_FILENO, TCSANOW, &newt );
    const int oldf = fcntl( STDIN_FILENO, F_GETFL, 0 );
    fcntl( STDIN_FILENO, F_SETFL, oldf | O_NONBLOCK );
    const int ch = getchar();
    tcsetattr( STDIN_FILENO, TCSANOW, &oldt );
    fcntl( STDIN_FILENO, F_SETFL, oldf );
    if( ch != EOF )
    {
        // ungetc(ch, stdin);
        return 1;
    }
 
    return 0;
}
#endif // #if defined(linux) || defined(__linux) || defined(__linux__) || defined(__APPLE__)
 
#endif // exampleHelperH