Can you post minimal code needed to reproduce the error? Also, what version of Win32::SerialPort and Perl are you using?

Looking at some old code of mine that used Win32::SerialPort, my code did do something along the lines of $serial->baudrate($baudrate); and it did work.

Out of curiosity, did you happen set the value of $baudrate like $baudrate = "38400";? If so, try changing that to be $baudrate = 38400; instead.

Try $Serial->baudrate(0+$baud_rate).

Thank you. But it does not work. Nor work similar other tricks like:

$Serial->baudrate(0+$baud_rate)

$Serial->baudrate(int($baud_rate))

$Serial->baudrate("$baud_rate")

$Serial->baudrate(eval{$baud_rate})

I don't know what it may be

Thank you. But it does not work. Nor work similar other tricks like:

$Serial->baudrate(int($baud_rate))
$Serial->baudrate("$baud_rate")
$Serial->baudrate(eval{$baud_rate})
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The following seems to work (in the sense that it does not produces an error message), but the serial stream does not have the baudrate it is supposed to have

$Serial->{"_L_BAUD"}{$baud_rate} = $baud_rate;
$Serial->baudrate($baud_rate);
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I don't know what it may be

It was my fault. The code was in a subroutine where $baud_rate was passed by reference and used as if it were passed by value. After correcting the mistake the following construct worked perfectly:

 
$Serial->{"_L_BAUD"}{$baud_rate} = $baud_rate;
$Serial->baudrate($baud_rate);
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