方法：使用宏定义，实现调试信息的可控输出

0.目标

使用宏定义，实现调试信息可控输出。可对调试信息进行等级分类，并分级输出调试信息，在嵌入式操作系统环境下（如VxWorks），还可以根据实际需求，打开或关闭对应等级的调试信息，方便bug排查。

1.代码

#include <stdio.h>

#define DBG_CAN_INFO g_dbg_can_info_level
#define DBG_TCP_INFO g_dbg_tcp_info_level
#define DBG_UDP_INFO g_dbg_udp_info_level
#define DBG_OTHER_INFO g_dbg_other_info_level

int g_dbg_can_info_level = 1;
int g_dbg_tcp_info_level = 2;
int g_dbg_udp_info_level = 3;
int g_dbg_other_info_level = 4;

#define DBG_LEVEL_MIN 1
#define DBG_LEVEL_MAX 5

#define PDEBUG(level, fmt, ...)                                                             \
	do                                                                                      \
	{                                                                                       \
		if ((level >= DBG_LEVEL_MIN) && (level <= DBG_LEVEL_MAX))                           \
		{                                                                                   \
			printf("DBG%d:%s(%d):" fmt "\n", level, __FUNCTION__, __LINE__, ##__VA_ARGS__); \
		}                                                                                   \
	} while (0)

int main()
{

	PDEBUG(DBG_CAN_INFO, "DBG_CAN_INFO=%d\n", g_dbg_can_info_level);
	PDEBUG(DBG_TCP_INFO, "DBG_TCP_INFO=%d\n", g_dbg_tcp_info_level);
	PDEBUG(DBG_UDP_INFO, "DBG_UDP_INFO=%d\n", g_dbg_udp_info_level);
	PDEBUG(DBG_OTHER_INFO, "DBG_OTHER_INFO=%d\n", g_dbg_other_info_level);

	printf("关闭UDP调试信息。\n");
	g_dbg_udp_info_level = 0; //关闭UDP调试信息

	PDEBUG(DBG_CAN_INFO, "DBG_CAN_INFO=%d\n", g_dbg_can_info_level);
	PDEBUG(DBG_TCP_INFO, "DBG_TCP_INFO=%d\n", g_dbg_tcp_info_level);
	PDEBUG(DBG_UDP_INFO, "DBG_UDP_INFO=%d\n", g_dbg_udp_info_level);
	PDEBUG(DBG_OTHER_INFO, "DBG_OTHER_INFO=%d\n", g_dbg_other_info_level);

	printf("打开UDP调试信息。\n");
	g_dbg_udp_info_level = 3; //再次打开UDP调试信息

	PDEBUG(DBG_CAN_INFO, "DBG_CAN_INFO=%d\n", g_dbg_can_info_level);
	PDEBUG(DBG_TCP_INFO, "DBG_TCP_INFO=%d\n", g_dbg_tcp_info_level);
	PDEBUG(DBG_UDP_INFO, "DBG_UDP_INFO=%d\n", g_dbg_udp_info_level);
	PDEBUG(DBG_OTHER_INFO, "DBG_OTHER_INFO=%d\n", g_dbg_other_info_level);

	return 0;
}
           

2.输出结果

DBG1:main(28):DBG_CAN_INFO=1

DBG2:main(29):DBG_TCP_INFO=2

DBG3:main(30):DBG_UDP_INFO=3

DBG4:main(31):DBG_OTHER_INFO=4

关闭UDP调试信息。
DBG1:main(36):DBG_CAN_INFO=1

DBG2:main(37):DBG_TCP_INFO=2

DBG4:main(39):DBG_OTHER_INFO=4

打开UDP调试信息。
DBG1:main(44):DBG_CAN_INFO=1

DBG2:main(45):DBG_TCP_INFO=2

DBG3:main(46):DBG_UDP_INFO=3

DBG4:main(47):DBG_OTHER_INFO=4
           

3.结果分析

可以看到，将全局变量g_dbg_udp_info_level赋值为0之后，调试信息“DBG3:main(30):DBG_UDP_INFO=3“消失了。再次将全局变量g_dbg_udp_info_level赋值为3之后，调试信息“DBG3:main(30):DBG_UDP_INFO=3“再次出现，实现了既定的目标。