Re: NSLog() and stderr

FROM : Frode
DATE : Sun Jul 02 10:51:49 2006

Hi!

1 jul 2006 kl. 03.09 skrev Damien Sorresso:

> I'm trying to redirect NSLog()'s output to a file. Since it writes 
> to stderr, I should be able to do this with
>
> stderr->_write = my_stderr_write ,
>
> where `my_stderr_write' is a pointer to one of my functions. This 
> works just fine if I use fprintf() to write to stderr, but NSLog() 
> stubbornly refuses to call my function. What exactly is NSLog() 
> doing here that is so special?


What exaclty capability  or behaviour are you expecting from the 
logging function and what will it be use for?

It sounds that you will need replace NSLog() with your own logging 
function "MyLog()".

void MyFLog(FILE *fp, NSString *format, ...) {
   va_list argList;
   va_start(argList, format);
   MyFLogv(fp, format, argList);
   va_end(argList);
}

void MyFLogv(FILE *fp, NSString *format, va_list argList) {
   int old_fd = dup(fileno(stderr));
   int new_fd = dup2(fileno(fp), fileno(stderr));

   NSLogv(format, argList);

   (void)dup2(old_fd, fileno(stderr));
}


FYI, you can use syslog(3) or perhaps asl(3). Logging is tuned by /
etc/syslog.conf and written to /var/log/*

Regards,
Rog