Debugging an app bundle on MacOSX

[Henrik Brautaset Aronsen]

I was trying to debug some stuff in Subsurface today, and stumbled upon 
some barriers when running it as an app bundle.

There are four ways of starting Subsurface:

1) Run the binary directly from the Terminal:  ./subsurface
2) Start the app bundle from the Terminal, with path reference:  open 
/Applications/Subsurface.app
3) Start the app bundle from the Terminal, with application reference:  
open -a Subsurface
4) Double-click the Subsurface icon in the /Applications folder.

The app bundle was generated with "make install-macosx".

Here's a simple example that I put on top of subsurface_ui_setup() in 
macos.c:

     FILE *file = fopen("/tmp/file.txt", "a+");
     if (file != NULL) {
         fprintf(file,"Silly test message");
         fclose(file);
     }
     syslog(LOG_ERR, "Another silly test message");

I had no problems when running as 1) or 2).  /tmp/file.txt was written 
to, and so was /var/log/system.log.

However, when run as 3) or 4), neither works.  Both operations fails 
silently.

Does anyone know what's going on here?  Mandatory sandboxing?  It's 
driving me quite mad.

Henrik