Re: differences between Ada and C in gnat forcing me to use C instead of Ada

[matthewbrentmccarty@gmail.com]

Hi all:
"gnat-gps" on my machine Windows 10 (debian subsystem for Linux) (see https://docs.microsoft.com/en-us/windows/wsl/install-win10 ) gives me "raised STORAGE_ERROR : s-intman.adb:139 explicit raise" yet the same software works fine on my "real" debian machine. The compiler works but gant-gps doesn't. 


For some reason when I call sane_get_devices as in:

      type Sane_Device_Ptr is access all sane_sane_h.SANE_Device;
      for Sane_Device_Ptr'Size use Standard'Address_Size;
      pragma Convention (C, Sane_Device_Ptr);

      type Device_Array is array (Integer range <>) of aliased Sane_Device_Ptr;
      pragma Convention (C, Device_Array);
      ...
      devices :  aliased  Device_Array (1..5);
      Status := sane_sane_h.sane_get_devices (devices(1)'Address, sane_sane_h.SANE_Bool(SANE_TRUE));

I get back garbage but in C, it works. Oh, now that makes sense about 'Size returning bits and sizeof in C returning bytes. 256 bits is indeed 32 bytes. I wonder why I'm getting back garbage. InterfaceS.C.Strings.chars_ptr'Size=64 and sizeof(char *)=8 are equivalent.

Thanks. I guess I got some more digging to do as to my garbage.

Regards,
Matthew McCarty