linux C/C++ 日志打印函数

//宏定义日志文件名

#define PROCESSNAME  "log_filename"

//当日志文件大于5M时，会删除该文件，该接口使用方法 参照printf
void WriteLog(const char *fm, ...)
{
    int buflen = ;
    char buf[buflen];
    int i = ;
    memset(buf, , buflen);
    va_list args;
    va_start( args, fm );
    vsnprintf(buf, buflen, fm,args);
    va_end( args );

    printf("%s\n", buf);
    FILE* logfile=NULL;
    char logpath[] = {};
    snprintf(logpath,sizeof(logpath),"/var/log/");
    if(access(logpath,)!=)
    {
        char cmdstr[] = {};
        sprintf(cmdstr,"mkdir -p %s",logpath);
        system(cmdstr);
    }

    char fname[];
    char longtime[];
    time_t t;
    memset(fname,,sizeof(fname));
    time(&t);
    struct tm local = {};
    localtime_r(&t, &local);
    sprintf(longtime,"%04d-%02d-%02d %02d:%02d:%02d", local.tm_year+,
            local.tm_mon+, local.tm_mday, local.tm_hour, local.tm_min, local.tm_sec);
    sprintf(fname,"%s/%s", logpath, PROCESSNAME);
    for(i= ; i < ; i++)
    {
        logfile = fopen(fname, "ab");
        if(logfile)
            break;
        sleep();
    }
    if(logfile)
    {
        // 判断文件大小
        if (ftell(logfile) < **)   // 5M
        {
            //日期时间
            const char* pTemp = longtime;
            fwrite(pTemp, , strlen(pTemp), logfile);
            fwrite(" ", , , logfile);
            //内容
            fwrite(buf, , strlen(buf), logfile);
            fwrite(" \r\n", , , logfile);
            fclose(logfile);
        }
        else
        {
            fclose(logfile);
            remove(fname);
        }
    }
}