ComSendBytes

This non-blocking function attempts to copy an application's data to internal communication port transmit buffers, constrained by the setting of the Mode parameter. It is very likely this function will return before the data copied into the internal buffers are completely transmitted. If the application needs to know when the data is completely transmitted, the ComXmitting call is provided.

Note that since System Manager calls can have significant overhead, it is advisable for the application to perform some level of local buffering and not perform character-at-a-time writes to the port's internal buffers.

Syntax:          err_t far ComSendBytes(handle_t Handle, char far *DataP, int Mode, 
                                        int far *DataLenP) 
Parameters:      int Handle - The handle returned via a successful ComOpen.  
                 char far *DataP - Far pointer to the buffer containing the data to 
                                   be sent int Mode A flag which specifies the mode 
                                   in which the data must be accepted by the 
                                   communication driver: 

                                   COM_CTL_WHOLE specifies that the application 
                                   wants all of the data to be copied into the 
                                   transmit buffer in one operation; partial sends are
                                   not permitted.  This option is useful when sending 
                                   protocol packets out, or when the application buffer
                                   must be reusable immediately after the ComSendBytes 
                                   call completes.  If the data cannot be copied into
                                   the internal buffer, then this call returns an 
                                   error, and no data is copied.

                                   Note that if the application specifies this option
                                   and specifies a buffer length that is larger than 
                                   the internal transmit buffer length, this call can
                                   never complete successfully. 

                                   COM_CTL_NORMALpermits partial writes.  

                 DataLenP - Far pointer to an integer which, on entry contains the 
                            number of bytes available in the application's buffer 

                            On exit, ComSendBytes sets this variable to the actual 
                            number of bytes copied from the application's buffer.  
Returns:         0 - if successful 
                 Any other value indicates an error condition.  
                 ENOTYOURS - The specified port has not been acquired by the calling 
                             application.  
Related Calls:   ComXmitting