Output syntax for waveOutGetVolume API

slloyd has asked for the wisdom of the Perl Monks concerning the following question:

Fello Monks, I am stumped on the output of the waveOutGetVolume Win32 API. Can anyone help me getting the proper output from this API call? I want to convert it to a number from 1-100 representing the volume percantage.

my $hwnd = shift || 0;
my $vol=" "x10;
$waveOutGetVolume ||= new Win32::API("Winmm", "waveOutGetVolume", ['N'
+,'P'], 'N') || return;
my $ck = $waveOutGetVolume->Call($hwnd, $vol);
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Comment on Output syntax for waveOutGetVolume API Download Code

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Re: Output syntax for waveOutGetVolume API by BrowserUk (Patriarch) on Jul 14, 2004 at 03:55 UTC
Derived from waveOutGetVolume `## following on from your code ## If the values are wacky try 'nn' instead of 'vv' my( $leftVol, $rightVol ) = unpack 'vv', $vol; my $leftPercent = $leftVol * 100 / 0xffff; my $rightPercent = $rightVol * 100 / 0xffff; ## Numerically correct if not to a sound engineer my $totalVolPercent = ( $leftPercent + $rightPercent ) / 2;` [download] Examine what is said, not who speaks. "Efficiency is intelligent laziness." -David Dunham "Think for yourself!" - Abigail "Memory, processor, disk in that order on the hardware side. Algorithm, algoritm, algorithm on the code side." - tachyon	[reply] [d/l]
Re^2: Output syntax for waveOutGetVolume API by slloyd (Hermit) on Jul 14, 2004 at 04:07 UTC
Thanks a lot. That worked great! For the record, here is the final code wrapped into a subroutine. sub getSoundVolume { #usage: $tpcnt=getSoundVolume($hwnd) or ($tpcnt,$lpcnt,$rpcnt)=get +SoundVolume($hwnd); #info: gets sound volume - $tpcnt is a number from 0 to 100. my $hwnd = shift \|\| 0; my $vol=" "x10; $waveOutGetVolume \|\|= new Win32::API("Winmm", "waveOutGetVolume", +['N','P'], 'N') \|\| return; my $ck = $waveOutGetVolume->Call($hwnd, $vol); my ($leftVol,$rightVol) = unpack 'vv', $vol; my $leftPercent = int($leftVol * 100 / 0xffff); my $rightPercent = int($rightVol * 100 / 0xffff); my $totalVolPercent = int(($leftPercent+$rightPercent)/2); if(wantarray){return ($totalVolPercent,$leftPercent,$rightPercent) +;} return $totalVolPercent; } [download]	[reply] [d/l]