Two Questions about Linking to C libraries

[Craig Dillabaugh]

I recently created bindings to the C libary shapelib.

http://shapelib.maptools.org/

I generated my own bindings by hand, and another set of bindings 
with DStep.

I created a small test program to test my bindings.  My current 
test program in its entirety is:

import std.stdio;
import std.string;
import std.conv;

import shapefil;

int main( string args[] )
{
   const char* filename = std.string.toStringz( args[1] );

   SHPHandle hShp = SHPOpen(filename, "rb");

   int num_entities;
   int shp_type;
   double pad_min_bound;
   double pad_max_bound;

   SHPGetInfo( hShp, &num_entities, &shp_type,
               &pad_min_bound, &pad_max_bound);

   writeln("Shapefile contains " ~ to!string(num_entities) ~ " 
entities.");
   writeln("Of type " ~ to!string( SHPTypeName( shp_type) ));
   writeln("Bounds = [" ~to!string(pad_min_bound) ~ ","
                        ~ to!string(pad_max_bound) ~ "]");

    SHPClose( hShp );
    return 0;
}

It simply reads a Shape File, the name for which is passed from 
the command line.

When I execute this I get the following message:

./shapetest data/dresden/gis.osm_water_v06.shp
Shapefile contains 799 entities.
Of type Polygon
Bounds = [13.5274,50.9632]
Segmentation fault

The first three lines output are what I expected, but then it 
segfaults on exit.
Running it in GDB I get the following error message:

Program received signal SIGSEGV, Segmentation fault.
0x0000000000443fc7 in rt.dmain2._d_run_main() ()

Printing the backtrace provides no additional information.  The 
same problem occurs whether I used my hand-rolled binds or the 
DStep version.

So my two questions are:

1. Does anyone have any idea why my program is segfaulting. It 
seems to crash at exit and I read somewhere (can't recall where) 
that uncollected C style strings may cause the GC to fail.  
Perhaps this is my problem.  I tried commenting out some of the 
statements (eg. the SHPTypeName( shp_type) line, which returns a 
"const char *", but I still get a segfault.  Any ideas on how to 
find the root cause?

2. Once I think my bindings are stable I would like to add them 
to Deimos or DUB registries.  Are there any recommendations for 
testing bindings? I checked through some other bindings on GitHub 
and didn't see any unit tests or the like. Are there any 'best 
practices' out there for testing bindings?