serial_connect.h

主要用于无线传感网络的编写的书籍.对于初学者有着很大的用处

#ifndef __SERIAL_CONNECT__
#define __SERIAL_CONNECT__
#include "../../types/types.h"

#define BYTETIMEOUT 10 // tenths of seconds

#ifndef SUCCESS
#define SUCCESS 1
#endif

#ifndef FAILURE
#define FAILURE 0
#endif

#define SERIAL_PORT_CLOSED -1

/************************************************************************
 * RULES:
 * 1.  You must call closeSerialPort with only the file descriptor 
 *     returned by openSerialPort.
 * 2.  If you call openSerialPort twice without calling closeSerialPort,
 *     you will get the same, already open, serial port desciptor back
 *     (i.e. it will not open two streams to the same port)
 *     even if you pass the function a new pathname.  In other words,
 *     there is a global flag that is set/reset by openSerialPort
 *     and closeSerialPort that does not keep track of the pathname.
 *     NOTE: this may be modified in the future
 * 3.  If you try to call closeSerialPort with anything other than 
 *     the open serial port file descriptor as a parameter, then
 *     it will instantly return failure.
 * 4.  Examples of how to read/write from/to the serial port are
 *     listed at the end of this file.
 ************************************************************************/

// returns a useable file descriptor on success, -1 on error
int openSerialPort(char *serial_port_filepath);

// returns SUCCESS on success, FAILURE on failure
int closeSerialPort(int serial_port_file_descriptor);

// flushes everything from input and output buffers
int flushInputPort(int serial_port_file_descriptor);
int flushOutputPort(int serial_port_file_descriptor);

/*******************************************************************************
 * HOW TO USE SERIAL_CONNECT:
 *
 * 1.  First, get a file descriptor:
 * 
 * fd = openSerialPort();
 * 
 * 2.  To write to the serial port:
 * 
 * ret_val = write(fd, "ATZ\r", num_bytes_to_write);
 * if (ret_val < 0) {
 *   fprintf(stderr, "write() of %d bytes failed!\n", num_bytes_to_write);
 * }
 * 
 * 3.  To read from serial port:
 * num_bytes_read = read(fd, &buffer, num_bytes_to_read);
 * if (num_bytes_read != num_bytes_to_read) {
 *   fprintf(stderr, "read() of %d bytes failed!\n", num_bytes_to_read);
 * }
 * NOTE: for mica2 motes, always read only one byte at a time
 *******************************************************************************/

#endif