fromt he copy of your github, looks like libusboop.pas has a uses
statement for libusb.pas; so libusb.pas is still used
https://github.com/Zaaphod/pas-libusb/blob/Hack/src/libusboop.pas (line 30)
Uses
Classes, SysUtils, LibUsb;
On 8/17/19 1:39 PM, James Richters wrote:
I think maybe it is the calling convention... First I tried to change
libusboop.pas (libusb.pas is the old unit, libusboop.pas is the one it uses) to
stdcall, I was unable to compile it, I get an error
libusboop.pas(1456,28) Error: Incompatible types: got "<address of
procedure(Plibusb_transfer);StdCall>" expected "<procedure variable type of
procedure(Plibusb_transfer);CDecl>"
libusboop.pas(1726) Fatal: There were 1 errors compiling module, stopping
I'm not sure where or how it's expecting CDecl or how to change that to use
stdcall.
So for fun I tried doing it the other way around, and changed libusbxhid to
cdecl... well it compiled ok but then I tried to run it I got this:
device attempting go clear halt on ep $81
libusb: error [hid_clear_halt] unable to match endpoint to an open interface -
cannot clear
clear halt failed
So I don't know what all that really means, but it was an endpoint match
problem causing access denied..... so maybe just need to figure out how to get
stdcall to properly work with pas-libusb.
James
-----Original Message-----
From: fpc-pascal <fpc-pascal-boun...@lists.freepascal.org> On Behalf Of Stefan
V. Pantazi
Sent: Saturday, August 17, 2019 12:11 PM
To: fpc-pascal@lists.freepascal.org
Subject: Re: [fpc-pascal] USB Human Interface Devices
Libusb can be compiled with either calling convention - one just has to be sure
which one.
In https://github.com/Zaaphod/libusbxhid/blob/master/libusbx.pas (line 35), the
windows calling convention is stdcall and that apparently works for both 64 and
32 bit windows. So, James' libusb10 dlls use stdcall.
Also, I was under the impression that unlike linux, Windows apps would compile
regardless of the calling convention. Only when launching the app and loading a
dynamic library a wrong calling convention make things blow up. Anyway, this is
definitely something to look into.
On 8/17/19 11:46 AM, Jean SUZINEAU wrote:
Le 17/08/2019 à 17:10, Stefan V. Pantazi a écrit :
The obvious first thing to make sure is that the calling convention
matches the library for the platform. I see that in
https://github.com/Zaaphod/pas-libusb/blob/Hack/src/libusb.pas 9line
46) the calling convention on Windows is cdecl (the stdcall is
commented out). In libusbxhid, if I remember correctly, the calling
convention for windows dlls is set to stdcall.
Yes it's curious.
Usually with Microsoft dlls from the Windows API, you use stdcall.
Here with stdcall I get an error "Import library not found for libusb-1.0".
So I commented out the stcall changed it to cdecl.
This allows to compile without errors and test1library.pas works
without error, it seems cdecl is the right calling convention for libusb-1.0.
One other thing is that debugging is much more tedious without an
integrated debugger that allows you to step through each line before
you can see which function call blows up with a segfault.
James works on the command line but fp.exe seems to integrate gdb.exe
the same way that lazarus does, you nearly have the same shortcuts
keys for debugging between Turbo Pascal 5.5, fp.exe and lazarus ...
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