COM_COUNT()
 Counts the number of characters in the input buffer
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 Syntax

     COM_COUNT(<nComPort>) --> nTotalCharacters

 Argument

     <nComPort>  Designates the port (1 to 4) for which the number of
     characters in the input buffer is determined.

 Returns

     COM_COUNT() returns the number of characters in the selected buffer.

 Description

     This function allows you to determine the number of characters in one of
     the four possible buffers.  This lets you determine how many characters
     can be read with the COM_READ() function.

 Note

     .  If an attempt is made to read the number of characters
        available in a closed port, the function returns a value of -1.

 Example

     nCharacter  :=  COM_COUNT(1)   // Number of characters-port 1

     IF nCharacter > 0
        COM_READ(1, 1)              // Read 1 character
     ENDIF