Output in Log file instead of Standard Input Output

srinietrx · 10-16-2015, 08:21 AM

I am developing C++ application.As size of the code increases, I feel my printf output needs to go to some file instead of stdio.

Is there is any standard class or I need to write code from scratch?

NevemTeve · 10-16-2015, 09:06 AM

If it is about error/debug-messages, they could be sent to stderr (cf: fprintf), to separate them from the normal output. stderr can be redirected from shell:

Code:

./myexe 2>messages.log

HMW · 10-16-2015, 09:33 AM

Or... if you simply want to write to a FILE instead of to stdout,

Code:

#include <fstream>

Sort of like this:

Code:

#include <iostream>
#include <fstream>
using namespace std;

int main() 
{
    ofstream log;
    log.open("cpp.log", ios::app);
    log << "Log entry here.\n";
    log.close();

    return 0;
}

So after executing the code above (named file_write):

Code:

./file_write

...three times, I get the following content in the file cpp.log:

Code:

cat cpp.log 
Log entry here.
Log entry here.
Log entry here.

But maybe that was too simple?

Best regards,
HMW

PS. Haven't used c++ in AGES. Please be gentle! DS.

srinietrx · 10-18-2015, 09:34 AM

Thanks.I want similar to what HMW has written.