LINUX下C语言编程怎么打印日志

将日志写到文件中去，在到文件中去看日志

例如：

int

mig_log(fmt,va_alist)

char

*fmt

va_dcl

{

va_list

ap

FILE

*fp

char

log_file[81]

struct

tm

*p_tm

time_t

clock

ap=(char

*)&va_alist

time(&clock)

p_tm=localtime(&clock)

sprintf(log_file,"%s/mig_%4d%.2d%.2d.log",

getenv("HOME"),

p_tm->tm_year+1900,

p_tm->tm_mon+1,

p_tm->tm_mday)

fp=fopen(log_file,"at")

if(fp==(FILE

*)0)

{

fprintf(stderr,"mig_err_log():can't

open

the

file

%s

!\n",log_file)

return

}

fprintf(fp,"%.2d/%.2d/%4d

%.2d:%.2d:%.2d

",

p_tm->tm_mon+1,\

p_tm->tm_mday,\

p_tm->tm_year+1900,\

p_tm->tm_hour,\

p_tm->tm_min,\

p_tm->tm_sec)

vfprintf(fp,fmt,ap)

fclose(fp)

}

这个就是写日志的函数

你这样调用：mig_log("日志开始[%s]->[%d]\n",__FILE__,__LINE__)

mig_log("日志开始!\n")都可以的

用我写的吧 实测过了的 可以直接使用

void WriteSysLog(char *str)

{

char buf[512]

long MAXLEN = 10*1024*1024//10MB

time_t timep

FILE *fp = NULL

struct tm *p

time(&timep)

p = localtime(&timep)

memset(buf,0,sizeof(buf))

sprintf(buf,"%d-%d-%d %d:%d:%d : ",(1900+p->tm_year),(1+p->tm_mon),\

p->tm_mday,p->tm_hour, p->tm_min, p->tm_sec)//星期p->tm_wday

strcat(buf,str)

strcat(buf,"\r\n")

fp = fopen("./syslog.log","r")

if(fp==NULL)

{

fp = fopen("./syslog.log","w+")

}

else

{

fseek(fp,0,2)

if(ftell(fp) >= MAXLEN)

{

fclose(fp)

fp = fopen("./syslog.log","w+")

//大于10MB则清空原日志文件

}

else

{

fclose(fp)

fp = fopen("./syslog.log","a")

}

}

fwrite(buf,1,strlen(buf),fp)

fflush(fp)

fsync(fileno(fp))

fclose(fp)

}

#include <stdlib.h>

#include <string.h>

#include <stdio.h>

#include <dirent.h>

#include <time.h>

#define LOGFILE "./dir_log_0"

int g_Count

//#define MAXLEN  1024

void WriteDebugLog(char *str)

int main(int argc, char **argv)

{

    char str[1024]={0}

    strcpy(str,"file no find")

    int i=0,j=0

    for (i=0i<10i++)

    {

        for (j=0j<50j++)

        {

            WriteDebugLog(str)    

        }

            

    }

    return 0

}

void WriteDebugLog(char *str)

{

    char buf[2048]={0}

    char logFileName[50]={0}

    //long MAXLEN = 50*1024*1024//50MB

    int iMax = 1024//1K

    time_t timep

    FILE *fp = NULL

    struct tm *p

    time(&timep)

    p = localtime(&timep)

    memset(buf,0,sizeof(buf))

    sprintf(buf,"[%d-%d-%d %d:%d:%d][DEBUG]",(1900+p->tm_year),(1+p->tm_mon), p->tm_mday,p->tm_hour, p->tm_min, p->tm_sec)//星期p->tm_wday

    strcat(buf,str)

    strcat(buf,"\r\n")

    strcpy(logFileName,LOGFILE)

    int len = strlen(logFileName)

    logFileName[len-1] = '0'+g_Count

    fp = fopen(logFileName,"r")

    if(fp==NULL)

    {

        fp = fopen(logFileName,"w+")

    }

    else

    {

        fseek(fp,0,2)//SEEK_END值为2

        if( ftell(fp) >= iMax)

        {

            fclose(fp)

                

            if (g_Count >= 9) 

            {

                logFileName[len-1] = '0'

                g_Count=0

            }

            else

            {

                g_Count++

                logFileName[len-1] = '0'+g_Count

            //  printf("\n%c",'0'+g_Count)

            }

            fp = fopen(logFileName,"w+")

        }

        else

        { 

            fclose(fp)

            fp = fopen(logFileName,"a")

        }

    }

    fwrite(buf,1,strlen(buf),fp)

    fclose(fp)

}

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