Re: [fpc-devel] JWA 64-bit struct packing
Op 2020-05-14 om 17:03 schreef Henry Vermaak via fpc-devel:
The original headers only did 32-bit. Over the years some 64-bit
corrections have been added. This process is ongoing, so please make
sure you use the newest version.
Grepping for align|packrecords give exactly the same results in trunk,
afaics. jwawindows.pas explicitly sets align 4.
jwawindows.pas
{$ALIGN 4}
{$ALIGN 4}
jwawinldap.pas
{$ALIGN ON}
jwawinsock2.pas
{$ALIGN 4}
jwaws2atm.pas
{$ALIGN ON}
jwaws2spi.pas
{$ALIGN OFF}
{$ALIGN ON}
But yeah, that looks bad.
I'm a bit loath to try to fix this with big, overarching $packrecords,
because the winapi actually sometimes uses packrecords C and sometimes
packrecords 8.
So why is rtl/win*/* full of packrecords c? These pages say that the
Windows API expect 8:
https://docs.microsoft.com/en-us/windows/win32/winprog/using-the-windows-headers#controlling-structure-packing
https://docs.microsoft.com/en-gb/cpp/build/reference/zp-struct-member-alignment
Those are probably the exceptions then. But jwa* is delphi compat, so
can't use $PUSH/$POP, so changing defaults is less useful, since it will
be undone at the first exception
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Re: [fpc-devel] JWA 64-bit struct packing
On Thu, 14 May 2020 at 16:03, Henry Vermaak wrote: > So why is rtl/win*/* full of packrecords c? These pages say that the > Windows API expect 8: > > https://docs.microsoft.com/en-us/windows/win32/winprog/using-the-windows-headers#controlling-structure-packing > https://docs.microsoft.com/en-gb/cpp/build/reference/zp-struct-member-alignment If I do something like `echo '#include ' | gcc -E -dMD -P - | grep -i pack` I get this: #undef _CRT_PACKING #define _CRT_PACKING 8 #pragma pack(push,_CRT_PACKING) #pragma pack(pop) Before any of wincred.h gets defined, so the packing gets popped and it'll use the natural packing for the structs in wincred.h, which is why packrecords c works in my code. How does one know which header uses 8 bytes and which uses natural packing? (Apart from checking mingw like this, which to be fair has never let me down with winapi programming). Henry ___ fpc-devel maillist - fpc-devel@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
Re: [fpc-devel] JWA 64-bit struct packing
On Thu, 14 May 2020 at 15:22, Marco van de Voort wrote: > The original headers only did 32-bit. Over the years some 64-bit > corrections have been added. This process is ongoing, so please make > sure you use the newest version. Grepping for align|packrecords give exactly the same results in trunk, afaics. jwawindows.pas explicitly sets align 4. > I'm a bit loath to try to fix this with big, overarching $packrecords, > because the winapi actually sometimes uses packrecords C and sometimes > packrecords 8. So why is rtl/win*/* full of packrecords c? These pages say that the Windows API expect 8: https://docs.microsoft.com/en-us/windows/win32/winprog/using-the-windows-headers#controlling-structure-packing https://docs.microsoft.com/en-gb/cpp/build/reference/zp-struct-member-alignment Henry ___ fpc-devel maillist - fpc-devel@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
Re: [fpc-devel] JWA 64-bit struct packing
Op 2020-05-14 om 15:53 schreef Henry Vermaak via fpc-devel:
I'm having some crashes and errors from 64-bit Windows builds that use
the JWA units. I've tracked it down to record alignment (the 32-bit
version works fine, so it's the first place I looked). I notice that
there's no {$packrecords c} anywhere (or alternatively {$align 8} for
64-bit). Am I missing something? I'm having trouble believing that
no one has found this before.
The original headers only did 32-bit. Over the years some 64-bit
corrections have been added. This process is ongoing, so please make
sure you use the newest version.
I'm a bit loath to try to fix this with big, overarching $packrecords,
because the winapi actually sometimes uses packrecords C and sometimes
packrecords 8.
Similar attempts in the normal windows headers were cumbersome, so we
are dealing with it on a case by case basis.
If you have problems with certain structures, AND you have tested with
trunk or FPC 3.2.0rc1, please file a bug.
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[fpc-devel] JWA 64-bit struct packing
I'm having some crashes and errors from 64-bit Windows builds that use
the JWA units. I've tracked it down to record alignment (the 32-bit
version works fine, so it's the first place I looked). I notice that
there's no {$packrecords c} anywhere (or alternatively {$align 8} for
64-bit). Am I missing something? I'm having trouble believing that
no one has found this before.
Henry
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