1 void log_file( const int pid,const char * str_fmt,...)
 2 {
 3     FILE *fp;
 4 
 5     fp = fopen("myfile.txt", "a");
 6    
 7     if(fp)
 8     {
 9         static char log_trace[256];
10         va_list ap;
11         struct tm *tm;
12         time_t t;
13     
14         va_start(ap, str_fmt);
15         vsnprintf(log_trace, sizeof(log_trace), str_fmt, ap);
16         va_end(ap);
17 
18         t = time(NULL);
19         tm = localtime(&t);
20         fprintf(fp, "[%02d/%02d/%02d/ %02d:%02d:%02d]: %s pid:%d\n", 
21                     tm->tm_year, 
22                     tm->tm_mon, 
23                     tm->tm_mday, 
24                     tm->tm_hour, 
25                     tm->tm_min, 
26                     tm->tm_sec,
27                     log_trace,pid);
28         fclose(fp);
29     }
30 
31 
32 }

比较常用的一种，还有其它的方式~后面再补充

转载于:https://www.cnblogs.com/heimi/archive/2013/04/11/3014355.html