How to write an C/C++ application that writes to a /var/log/myapp directory?

Question

Background

On Linux systems, Application Logs exist in subdirectories of /var/log, which is owned by root/root and has 755 permissions on my system. For example, I see /var/log/mysql and /var/log/samba.

Question

If I want a myapp to be able to write into a /var/log/myapp, what is the canonical way of accomplishing this in C/C++?

Thoughts

Do I have to do something crazy like setuid root if I don't want to sudo a_setup_script.sh? Note that I am aware of the syslog routines, but they are insufficient for my needs (I need to log much more information, separated into different files, hence the need for the subdirectory).

Do I need to look into a combination of Ubuntu packaging (to set up the directory) and direct file IO into the subdirectory (by myapp)?

I would like to follow standards as much as possible.

Addendum

I forgot to mention, myapp is actually a daemon processes (a server that listens to clients) so it wouldn't be so bad to have a myapp_user which actually runs/starts the process.

ANSWER

For Ubuntu, the best solution appears to be rsyslog, a powerful, modern replacement for syslog. It will generate files/directories as necessary, it has a built-in language for flexible routing of syslog entries, and it uses the simple, old syslog API at the C/C++ level. To store routing information, you can define your own encoding of the text message in C/C++, in conjunction with a proper rsyslog.conf to handle the decoding.

Answer 1

No, no no no. No suid for such stuff. These logs are managed by a process known as "syslog" and there is an API to send messages to this logger:

   void openlog(const char *ident, int option, int facility);
   void syslog(int priority, const char *format, ...);
   void closelog(void);

Or you can type 'man syslog' on the command line and get all the info :-)

Update: you will need permissions to edit syslog's configuration file to send message to a separate log file, otherwise they will end up in the default location (probably /var/log/syslog).