Performs a write on the connection. 
- Parameters:
 - 
  
     | g  | Connection's handle.  | 
     | buffer  | The user's write buffer. To send a Galil command, a terminating carriage return is usually required.  | 
     | buffer_len  | The length of the data in the buffer. | 
  
   
- Returns:
 - The success status or error code of the function. See gclib_errors.h for possible values. If G_NO_ERROR is returned, all bytes were written.
 
See x_gread_gwrite.cpp for an example.