Hi Dana,

You may want to look at using SetDllDirectory <https://msdn.microsoft.com/en-us/library/windows/desktop/ms686203%28v=vs.85%29.aspx> as this allows the DLL directory to be explicitly specified.


Regards,
Dave

On 4/03/17 5:25 AM, Dana Robinson wrote:
Hi all,

I've created a JIRA issue for this request. For future reference, it's 
HDFFV-10143 in our system.

Cheers,

Dana


-----Original Message-----
From: Hdf-forum [mailto:[email protected]] On Behalf Of 
[email protected]
Sent: Friday, March 3, 2017 11:06 AM
To: [email protected]
Subject: Re: [Hdf-forum] Setting plugin path programmatically


Hi Dana,

Setting the plugin path programmatically will be very useful for those 
applications that bundle filters too as this will simplify their installation 
procedure.

Regards,
  Peter


-----Original Message-----
From: Hdf-forum [mailto:[email protected]] On Behalf Of Dana 
Robinson
Sent: 03 March 2017 15:58
To: HDF Users Discussion List <[email protected]>
Subject: Re: [Hdf-forum] Setting plugin path programmatically

Hi Andrey,

I'll create an issue for this. We have a Windows layer that substitutes Win32 
equivalents for some POSIX commands and it should be straightforward to use 
SetEnvironmentVariable() on Windows.

Dana Robinson
Software Engineer
The HDF Group

-----Original Message-----
From: Hdf-forum [mailto:[email protected]] On Behalf Of 
?????? ?????????
Sent: Friday, March 3, 2017 3:43 AM
To: HDF Users Discussion List <[email protected]>
Subject: [Hdf-forum] Setting plugin path programmatically

Hello!

My usage scenario is a big Windows application with a lot of dlls, some of 
which use HDF5 library. HDF5 code uses Dynamically Loaded Plugin Filters:
https://support.hdfgroup.org/HDF5/doc1.8/Advanced/DynamicallyLoadedFilters/HDF5DynamicallyLoadedFilters.pdf

The filters are deployed in a local directory which is activated via modifying 
process HDF5_PLUGIN_PATH env.variable, just prior to loading the library. That 
works fine, and important thing is that user can just drop new plugins in that 
directory to support newer files.

However, it appears that in some cases plugin search fails. HDF5 library 
retrieves HDF5_PLUGIN_PATH via HDgetenv which is defined as
#define HDgetenv(S)    getenv(S)

According to
http://stackoverflow.com/questions/10636768/does-getenv-cache-the-result/10636993#10636993
"A process inherits the environment from the process creating the new process. This 
is held in memory."

In the application I do not use C runtime (the implementation language is not 
C), so I use SetEnvironmentVariable:
https://msdn.microsoft.com/ru-ru/library/windows/desktop/ms686206(v=vs.85).aspx

It appears that if I modify HDF5_PLUGIN_PATH before C runtime is loaded for the 
first time in the application, all is fine. However if I call 
SetEnvironmentVariable after C runtime is already loaded, it has no effect for 
HDF5.

The application is huge, and it's very hard to control the moments C runtime 
and HDF5 library are loaded. I wonder -- does it make sense to add HDF5 
procedures to verbosely modify plugin search path, something like

herr_t H5PLadd_path(const char *name)
herr_t H5PLrem_path(const char *name)

?

The above procedures could use HDsetenv, which is otherwise not accessible 
(from non-C applications).
(I think similar motivation led to exposing H5free_memory procedure.)

What do you think?

Best wishes,
Andrey Paramonov

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_______________________________________________
Hdf-forum is for HDF software users discussion.
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Twitter: https://twitter.com/hdf5


_______________________________________________
Hdf-forum is for HDF software users discussion.
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