Unix下C语言用于记录日志的方法(自定义)

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/time.h>#include <pthread.h>#include <time.h>#include <sys/timeb.h>#include <stdarg.h>/* * 此方法改自csdn大牛zhao4zhong1的代码 * 此程序用于记录日志，运行环境为linux，线程安全，单个日志文件的最大字节数为LOGMAXSIZE字节。 * MyLog1.log存储较新的日志，MyLog2.log存储MyLog1.log前面的日志（大小为LOGMAXSIZE字节）。 */#define LOGMAXSIZE (10 * 1024 * 1024)//日志文件最大为10M#define LOGMAXLINSIZE 2048char logfilename1[]="MyLog1.log";char logfilename2[]="MyLog2.log";static char logstr[LOGMAXLINSIZE+1];/*用于存储当前时间，时间精确到微秒*/char datestr[16];char timestr[16];char mss[4];pthread_mutex_t cs_log;FILE *flog;void LogV(const char *pszFmt,va_list argp){    struct tm *now;    struct timeb tb;    if (NULL==pszFmt||0==pszFmt[0])    return;    vsnprintf(logstr,LOGMAXLINSIZE,pszFmt,argp);    ftime(&tb);    now=localtime(&tb.time);    sprintf(datestr,"%04d-%02d-%02d",now->tm_year+1900,now->tm_mon+1,now->tm_mday);    sprintf(timestr,"%02d:%02d:%02d",now->tm_hour     ,now->tm_min  ,now->tm_sec );    sprintf(mss,"%03d",tb.millitm);//    printf("%s %s.%s %s",datestr,timestr,mss,logstr);    flog=fopen(logfilename1,"a");    if (NULL!=flog)    {        fprintf(flog,"%s %s.%s %s",datestr,timestr,mss,logstr);        if (ftell(flog)>LOGMAXSIZE)        {            fclose(flog);            if (rename(logfilename1,logfilename2))            {                remove(logfilename2);                rename(logfilename1,logfilename2);            }        }        else{            fclose(flog);        }    }}void Log(const char *pszFmt,...){    va_list argp;    pthread_mutex_lock(&cs_log);    va_start(argp,pszFmt);    LogV(pszFmt,argp);    va_end(argp);    pthread_mutex_unlock(&cs_log);}int main(int argc,char * argv[]){    int i;    pthread_mutex_init(&cs_log,NULL);    for (i=0;i<1000000;i++)    {        Log("This is a Log %04d from FILE:%s LINE:%d\n",i, __FILE__, __LINE__);    }    pthread_mutex_destroy(&cs_log);    return 0;}