empty PATH, LD_LOAD_PATH default

[Reini Urban]

I have a minor compatibility problem.

In Linux and other unices it is valid to start a process with an empty 
path because the LD_LOAD_PATH is correctly set to resolve the path for 
dynamic libraries.
I have this situation in perl TAINT-checked environments.
Our dll loader cannot handle LD_LOAD_PATH because in the case of linked 
shared libs we don't have our own loader, besides doing the dynamic dlopen.

So in linux et al. it is valid to do:
$ PATH= ./someprog-with-dependent-so
because linux has LD_LOAD_PATH and paths from /etc/ld.so.conf
while under cygwin it will fail.

Is there some fast way in the environment handling of the startup from 
cygwin processes before CreateProcess with a cygwin binary to detect an 
empty PATH, to mimic the behaviour of
   LD_LOAD_PATH=/usr/bin:$SYSTEMROOT/System32
Setting PATH to "/usr/bin/:$SYSTEMROOT:$SYSTEMROOT/System32"
to resolve the dll's to please the kernel loader.

Or is this a stupid idea? It would make process slower I assume if we 
want to detect the dependency of shared libs in processes to be created.

I do not know how the situation of an empty PATH in cygwin
should be handled.
cygcheck does write "WARNING: PATH is not set at all!"
Currently the process fails to start, which seems logic, but is a bit 
incompatible.

-- 
Reini Urban
http://phpwiki.org/  http://murbreak.at/
http://helsinki.at/  http://spacemovie.mur.at/

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