app-bundle vs. regular/"BSD utility" executables : what differences are there still?
René J.V. Bertin
rjvbertin at gmail.com
Tue Jan 5 11:35:27 PST 2016
On Tuesday January 05 2016 10:29:41 Jeremy Huddleston Sequoia wrote:
> There are really two main difference between the two cases:
> 1) The app bundles have an inherent main bundle (ie: [NSBundle mainBundle]).
But CFBundleGetMainBundle() does return something equivalent for non-bundled applications...
> 2) Apps are (usually) launched by LaunchServices. You can exec them directly, but that is not the preferred way to do it (and may not always work in the future).
> It's certainly possible for processes to draw GUI elements without being bundled, but it's less trivial.
That's the impression I had, but I haven't been able to confirm that recently, other than a subtle difference if you invoke the bundle exec via its full path or via a symlink.
Interaction with the elements can be more tricky; Qt5 applications I exec directly often do not show the menubar immediately until I cycle the foreground application. I suspect this has to do with the fact that Qt5 calls [NSApplication activateIgnoringOtherApps:] quite early (too early) during initialisation.
> It's possible for a standalone executable to have an Info.plist. It is embedded in the executable in an __info_plist section. This can be done by the CREATE_INFOPLIST_SECTION_IN_BINARY Xcode build setting or by creating an __info_plist section manually at link time if not using Xcode (-Wl,-sectcreate,__TEXT,__info_plist,/path/to/my/Info.plist).
I usually use CFBundleGetInfoDictionary() and CFDictionarySetValue(), but embedding the infodict like above is certainly easier once it contains more than 1 or 2 elements!
> As far as spawning processes in general, please don't use system() or fork()/exec(). Please use the posix_spawn syscall instead as it is much cleaner and has less overhead.
I'm not really familiar with that API, but a quick look suggests that the variant for spawning in "non-detached" fashion (spawnfd) is missing, correct?
> The open utility is basically a CLI to LSOpenURLsWithRole(). It does not exec or spawn anything. It just calls into LSOpenURLsWithRole().
Hmm, ok. I once wrote an alternative, but I cannot remember exactly why. Looks like I only simplified the calling syntax (`osxlaunch [-W] command [arguments]`).
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