Re: [PATCH] cygwin/mingw: binary wrapper fails when invoked via $PATH

[Charles Wilson]

Bob Friesenhahn wrote:

> Do you *know* exactly how Windows locates executables?  I thought 
not. :-)

Actually, I *DO* know exactly how a CYGWIN/MSYS shell locates 
executables.  And that's the point -- when you're using libtool, you're 
not in a DOSbox or double-clicking in a GUI.  You're in some sh.exe 
environment, which explicitly calls execlp (actually, execvp, but that's 
a nitpick).

Somewhere down in the bowels of the shell's (sh.exe) runtime library 
(either cygwin1.dll or msys-X.dll), that execvp call will eventually 
call CreateProcess() -- but it passes an explicit, fully specified 
pathname when it does so.

Cygwin/msys shells do not rely on magic windows exe-locating ESP.

> Unlike Unix, Windows uses the PATH as a means of last resort.  It
> performs a series of checks (likely Windows version dependent) before
> it gives up and uses the PATH.  It may be that for libtool's purposes,
> the PATH will always be used so your method will always work.
>
> One thing to consider is that GetModuleFileName() will execute faster
> than a method which executes a series of stat() calls and that users
> will likely appreciate it if their program runs sooner.

Now, that's true -- but unless your path is ridiculously long, or 
includes dead SMB shares -- you really won't notice the difference.  And 
if you DO have a ridiculous path, or dead SMB shares, then interactive 
behavior in the shell (you're using a unixish shell, right?) sucks anyway.

But all that's by the by.  As I see it there's only one question:

Shall the wrapper code be portable, or narrowly tailored to the 
platforms that currently need binary wrappers?

If you want portable, then my way is right.  If you want a narrowly 
tailored solution (simpler code, easier maintainability -- at least 
until you need to port similar functionality to non-windows, lower 
probability of bugs) then your way is right.

So, it's a policy decision -- and maintainers make policy, not 
contributors.  I'm a contributor, you're a maintainer.

What's your pleasure?

--
Chuck