C language debugging means: lock error implementation method

In the project development project, if can determine which file under Which line under which function went wrong -- that is, the locking error That would be nice. That's what this article is about.
First, let's take a look at the default output function of the file:
File information function:

printf("line : %dn", __LINE__);                   //The current line number
printf("filename : %sn", __FILE__);             //Current file name
printf("function : %sn", __FUNCTION__);  //The current function
printf("time : %sn", __TIME__);                  //The current time
printf ("date : %sn",  __DATE__);              //The current date
 Output: 
line : 10
filename : test.c
function : main.c
time : 14:13:51
date : Oct 13 2012

Now that the theory is complete, let's take a look at how to lock errors:
I. source file:

[root@localhost for_test]# cat erroutput.c
#include <stdio.h>
#include <assert.h>
#define _DEBUG(msg...)    printf("[ %s,%s, %d ]=>",__FILE__, __FUNCTION__, __LINE__);  printf(msg);printf("rn")
#define _ERROR(msg...)    printf("[ error: %s, %d]=>", __FILE__,  __LINE__);printf(msg); printf("rn")
#define _ASSERT(exp)      
                        do {
                                if (!(exp)) {
                                printf( "[ %s ]  ",#exp);printf("rn");
                                assert(exp);
                                }
                        } while (0)
int main(void)
{
        char *p = NULL;
        _DEBUG("DEBUG!");
        _ERROR("ERROR!");
        _ASSERT(NULL != p);
        return 0;
}

Ii. Output:

[root@localhost for_test]# gcc erroutput.c
[root@localhost for_test]# ./a.out
[ erroutput.c,main, 17 ]=>DEBUG!
[ error: erroutput.c, 18]=>ERROR!
[ NULL != p ]
a.out: erroutput.c:19: main: Assertion `((void *)0) != p' failed.
 Have to give up 

TI:

#ifdef DEBUG
    #define DBG(fmt, args...)  printf("Debug " fmt, ##args)//The ## operator is used to connect parameters together. The preprocessor merges the arguments that appear on either side of ## into a symbol.
#else
    #define DBG(fmt, args...)
#endif
#define ERR(fmt, args...)  printf("Error " fmt, ##args)
[root@localhost for_test]# cat debug_err.c
#include <stdio.h>
//#define DEBUG
int main(void)
{
       DBG("xxxxn");
       ERR("xxxxn");
       return 0;
}
[root@localhost for_test]# ./a.out
Error xxxx

#ifdef __DEBUG
    #define DBG(fmt, args...) fprintf(stderr,"Encode Debug: " fmt, ## args)
#else
    #define DBG(fmt, args...)
#endif
#define ERR(fmt, args...) fprintf(stderr,"Encode Error: " fmt, ## args)