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[netCDFJava #MDA-777673]: netcdf-4 library loading

Hi Vikram,

> I used Nc4Iosp.SetLibraryAndPath() to specify a location that does not
> exist, but there was no error message or failure.

Nc4Iosp.setLibraryAndPath() doesn't actually attempt to load libnetcdf, which 
is why you aren't seeing an error. Instead try something like:
        Nc4Iosp.setLibraryAndPath("/Users/cwardgar/Desktop/foo", "netcdf");
        System.out.printf("libnetcdf is present = %s%n", 
Nc4Iosp.isClibraryPresent());

When I've given the wrong path I get:
    Jul 27, 2016 4:26:49 PM ucar.nc2.jni.netcdf.Nc4Iosp load
    WARNING: Nc4Iosp: NetCDF-4 C library not present 
(jna_path='/Users/cwardgar/Desktop/foo', libname='netcdf').
    java.lang.UnsatisfiedLinkError: Unable to load library 'netcdf': Native 
library (darwin/libnetcdf.dylib) not found in resource path ([...])
        at com.sun.jna.NativeLibrary.loadLibrary(NativeLibrary.java:271)
        ...

Note that you'll need an SLF4J logger [1] on the classpath to see that message.

>Is there a path it defaults to looking for the library in?

The shared library loader on your system has a default search path [2], but 
NetCDF-Java doesn't (anymore). For example, if your binaries are in 
/usr/local/lib, they'll almost certainly be found without any extra effort from 
you.

> Also, I was wondering if the netcdf-Java classes relevant to netcdf-4 IO
> could be repackaged in a smaller jar file?

Do you use Maven or Gradle? If so, you only need to include the "netcdf4" 
module [3]. Then, all of its transitive dependencies will be pulled in 
automatically.

Or maybe you want a fat jar like netcdfAll.jar that includes everything 
necessary to work with NetCDF-4, and nothing else? If so, that's not an 
artifact we normally publish. I could easily build one for you if you want, but 
it's be a one-off.

Cheers,
Christian

[1] 
http://www.unidata.ucar.edu/software/thredds/current/netcdf-java/reference/BuildDependencies.html#_logging
[2] 
http://www.unidata.ucar.edu/software/thredds/current/netcdf-java/reference/netcdf4Clibrary.html#loading
[3] 
http://www.unidata.ucar.edu/software/thredds/current/netcdf-java/reference/netcdf4Clibrary.html

Ticket Details
===================
Ticket ID: MDA-777673
Department: Support netCDF Java
Priority: Normal
Status: Closed
===================
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