COM_SCOUNT()
 Counts the number of characters in the background sending buffer
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 Syntax

     COM_SCOUNT(<nComPort>) --> nLength

 Argument

     <nComPort>  Designates the port (1 to 4) for which the send buffer
     length is returned.

 Returns

     COM_SCOUNT() returns the number of characters in the sending buffer of
     the selected port.

 Description

     COM_SCOUNT() determines the number of characters in one of the four
     possible sending buffers.  This is only possible when the com interface
     is interrupt controlled, meaning that data is sent in the background.

 Note

     .  If you attempt to determine the character count in a port that
        is not open, the function returns a value of -1.

 Example

     nCharacter := COM_SCOUNT(1)            // Number of characters
                                            // in Port 1