Linux Write log file __linux

Call the Errorlog function to write the custom struct error_message type of data to the specified logfile file

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/signal.h>
#include <time.h>
#include <errno.h>
struct Error_message
{
time_t occur_time;//when the error occurred
const char * filename;//files that produce errors
int occur_no;//The line number where the error occurred
const char *error_content;//the contents of the error
};
typedef struct ERROR_MESSAGE error_message_t;
void errorlog (const char* logfile, error_message_t *emt)
{
FILE *FP;
struct TM ts;
Char time[20];
int exist=0;
Localtime_r (& (Emt->occur_time), &ts);

sprintf (Time, "%04d.%0 2d.%0 2d%02d:%02d:%02d ", ts.tm_year+1900,ts.tm_mon+1,ts.tm_mday,ts.tm_hour,ts.tm_min,ts.tm_sec);

Exist=access (LOGFILE,F_OK)//To determine whether the file exists, does not exist return-1

Fp=fopen (LogFile, "A +");
if (fp!=null)
{
if (exist<0)
{//file does not exist
fprintf (FP, "%20s/t%20s/t%5s/t%s/n", "Error Time", "filename", "line number", "Error content");
}

fprintf (FP, "%s/t%s/t%d/t%s/n", time,emt->filename,emt->occur_no,emt->error_content);
}
Else
{
printf ("error:%s/n", Strerror (errno));
}
Signal (Sigxfsz, SIG_DFL);
Fclose (FP);
}

int main (int argc,char **argv)
{
error_message_t EMT;
Bzero (&emt,sizeof (EMT));
Time (& (Emt.occur_time));
emt.filename=__file__;
emt.occur_no=__line__;
emt.error_content= "Test";
Errorlog ("/home/henry/stat/logfile.txt", &emt);
}

Sometimes we have the need to delete a file that has expired in a directory that can be implemented by the following function:

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <time.h>
#include <string.h>
#include <errno.h>

void Clean_file (char* cleandir,int days)
{//delete files for days before the Cleandir directory
DIR *dir;
struct Dirent *de;
struct stat buf;
time_t Tim;
int i;
Dir=opendir (Cleandir);
if (dir==null)
{
printf ("Open Directory%s error:%s/n", Cleandir,strerror (errno));
Return
}
ChDir (Cleandir);
while ((De=readdir (dir))!=null)
{
Bzero (&buf,sizeof (BUF));
I=lstat (DE-&GT;D_NAME,&AMP;BUF);
if (i<0)
{
printf ("i=%d,de->d_name=%s/n", i,de->d_name);
Break
}
Else
{
if (S_isdir (Buf.st_mode))
{
if ((strcmp (De->d_name, ".") ==0) | | (strcmp (De->d_name, "...")) ==0)
Continue
Clean_file (de->d_name,days);
}
Else
{
Time (&tim);
if (tim-days*24*60*60>buf.st_mtime)
{
printf ("Delete file:%s/n", de->d_name);
Unlink (de->d_name);//delete file
}
}
}
}
Closedir (dir);
}

int main ()
{
Clean_file ("/home/henry/programtest", 30);
}

The program has a flaw, that is, for programtest can not have more subdirectories.

You can start a program from a shell script, script content:

#!/bin/sh

/home/henry/programtest/cleanfile

Exit

Where/home/henry/programtest/cleanfile is the path to the executable file