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Full Discussion: C++, std:ofstream, and controlling an amplifiers mute function
Top Forums Programming C++, std:ofstream, and controlling an amplifiers mute function Post 303029758 by Circuits on Thursday 31st of January 2019 03:18:29 PM
Old 01-31-2019
C++, std:ofstream, and controlling an amplifiers mute function
Recently, I updated the unit I am running applications on with a new CODEC and amplifier; the older parts are EOL. There was a bug with the old setup. For some reason, even when a tone was not being generated, you could hear a noise emanating from the speaker when the LCD brightness was on a higher setting.


In order to counteract that problem the Amplifiers mute function (standby for old amp) was toggled on and off before and after a tone was produced:


Code:
const char *const amplifierGPIO = "/sys/class/gpio/gpio107/value";

    void amplifierOn()
    {
      std::ofstream amp(amplifierGPIO);
      if (amp.is_open())
      {
        amp << "1";
        amp.close();
      }
    }

    void amplifierOff()
    {
      std::ofstream amp(amplifierGPIO);
      if (amp.is_open())
      {
        amp << "0";
        amp.close();
      }
     }

The problem is that now in order to get the same functionality to work with the new amplifier I have to surround the ofstream in sleep statments:


Code:
const char *const amplifierGPIO = "/sys/class/gpio/gpio107/value";

    void amplifierOn()
    {
      sleep(1);
      std::ofstream amp(amplifierGPIO);
      if (amp.is_open())
      {
        amp << "1";
        amp.close();
      }
      sleep(1);
    }

    void amplifierOff()
    {
      sleep(1):
      std::ofstream amp(amplifierGPIO);
      if (amp.is_open())
      {
        amp << "0";
        amp.close();
      }
      sleep(1);
     }

1) Any ideas about why this might be the case? I do not believe it's the mute function on the amplifier itself because outside of the application that uses this ofstream (inside the boot loader) I can play a song and toggle it on and off with the mute function, with no delay needed.


2) Is there another way (other than ofstream) of toggling the GPIO pin 107 from within my application?
 

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LEARN ABOUT REDHAT

tiffregistercodec

CODEC(3T)																 CODEC(3T)

NAME

       TIFFFindCODEC, TIFFRegisterCODEC, TIFFUnRegisterCODEC - codec-related utility routines

SYNOPSIS

       #include <tiffio.h>
       const TIFFCodec* TIFFFindCODEC(uint16 scheme);
       TIFFCodec* TIFFRegisterCODEC(uint16 scheme, const char* method, TIFFInitMethod init);
       void TIFFUnRegisterCODEC(TIFFCodec* codec);

DESCRIPTION

       libtiff	supports a variety of compression schemes implemented by software codecs.  Each codec adheres to a modular interface that provides
       for the decoding and encoding of image data; as well as some other methods for initialization, setup, cleanup, and the control  of  default
       strip and tile sizes.  Codecs are identified by the associated value of the TIFF Compression tag; e.g. 5 for LZW compression.

       The  TIFFRegisterCODEC  routine	can be used to augment or override the set of codecs available to an application.  If the specified scheme
       already has a registered codec then it is overridden and any images with data encoded with this compression scheme will	be  decoded  using
       the supplied coded.

DIAGNOSTICS

       No  space  to register compression scheme %s.  TIFFRegisterCODEC was unable to allocate memory for the data structures needed to register a
       codec.

       Cannot remove compression scheme %s; not registered.  TIFFUnRegisterCODEC did not locate the specified codec in	the  table  of	registered
       compression schemes.

SEE ALSO

       libtiff(3T)

								 October 15, 1995							 CODEC(3T)
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