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 COM_SEND()
 Transmits data directly or in the background
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 Syntax

     COM_SEND(<nComPort>,<cString>) --> nLength

     Tip:  An enhancement over previous versions is that there are no new
     parameters!

 Arguments

     <nComPort>  Designates the port (1 to 4) from which transmission
     occurs.

     <cString>  Designates the string that is transmitted by the selected
     port.  If you only need to transmit a single character, then the second
     parameter can also be numeric and thereby pass the ASCII character code
     directly.

 Returns

     When transmission is successful, a 0 is returned.  If transmission is
     not successful, the number of characters that have not been transmitted
     or could not be placed in the sending buffer is returned.

 Description

     COM_SEND() transmits one or more characters from one of four ports.
     This transmission can be interrupt driven (i.e. occurs in the
     background).  The third parameter of COM_OPEN() determines whether or
     not the transmission is direct or occurs in the background.

     "Normal" Transmission
     During "normal" transmission, program execution can continue only when
     all of the characters have been sent to the port.  A unique situation
     presents itself when the hardware handshake is activated.  As soon as
     the receiving station deactivates the CTS signal from the sending
     station, any transmission is immediately stopped.  To prevent the
     CA-Clipper program from hanging, COM_SEND() is terminated and a numeric
     value representing the number of characters not yet sent is returned.
     COM_CTS() can determine if CTS input has been deactivated by the remote
     station.  The software handshake is not supported in this mode!

     Background Transmission
     The background mode supports software and hardware handshakes.  The
     handshake automatically occurs in the background.  Several new functions
     are available to help you maintain control of the transmission buffer in
     this situation.  For example, COM_SMODE() allows you to determine if the
     buffer is waiting for an XON character to release the software
     handshake.  Since this kind of wait can prove futile, you can use
     COM_FLUSH() from within the program to empty the transmission buffer.

 Notes

     .  The handshake is only supported when the transmission buffer
        is sending in the background.  Use small packets during direct
        transmissions, and regularly query COM_SOFT_R().

     .  Software and hardware handshakes are switched on using the
        COM_SOFT() and COM_HARD() functions.

 Examples

     .  This is an example of "normal" transmission at port 1, with no
        transmission buffer open:

        COM_OPEN(1, 1000)                    // Receiving buffer only
        COM_HARD(.T.)                        // Hardware handshake
        ACCEPT "Please input name " TO cInput
        nRest := COM_SEND(1, cInput)         // 1st attempt to transmit

        DO WHILE nRest > 0
           cInput := RIGHT(cInput, nRest)    // Characters not yet sent
           nRest := COM_SEND(1, cInput)
        ENDDO

     .  Here is an example for background or interrupt controlled
        transmission at port 1.  Everything else can proceed through "normal"
        transmission:

        COM_OPEN(1, 1000, 1000)           // 1000 byte transmission buffer
        nRest := COM_SEND(1, "Attempt")   // Place characters in buffer