Byte PTR

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stefan.ungemach
Posts: 71
Joined: Thu Jul 15, 2021 10:46 am
Location: Germany

Byte PTR

Post by stefan.ungemach »

Hi all,

I have some code to be migrated from VO to X# which simulates kind of a low-level wildseek with ADS functionality.

There is a variable

LOCAL pR as Byte PTR

which is at some point calculated from another pointer (it all comes down to do something with DBF headers):

pRecBuf := memAlloc(dwBufSize + 5)
pR := pRecBuf + 4

Later this goes into a function like this

ACE.ADSGetRecord(hTbl, pR, pRS)

where the function now does expect a BYTE[] for pR - so the compiler throws an error XS1503. Can someone please point me in the right direction how to deal with pR so that all the pointer arithmetics still work?
ic2
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Location: Holland

Byte PTR

Post by ic2 »

Hello Stefan,

Looking at Meinhards reply in a comparable case (https://www.xsharp.eu/forum/public-vo-v ... type#20466) I'd say this could work:(not tested & not sure if it actually does with BYTE[]) but you could quickly give it a try:

Code: Select all

BYTE[](_CAST, pR)
Dick
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robert
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Location: Netherlands

Byte PTR

Post by robert »

Stefan,
This is difficult without seeing what you are doing with the pR.
And what are you doing with the first 4 bytes?

To allocale the byte array you could use

pBytes := Byte[]{ (INT) dwBuffSize)

If you want to keep using the ptr, you can allocate the byre array and then use Marshal.Copy() to copy the bytes to the pointer.
Robert
XSharp Development Team
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robert@xsharp.eu
stefan.ungemach
Posts: 71
Joined: Thu Jul 15, 2021 10:46 am
Location: Germany

Byte PTR

Post by stefan.ungemach »

Dick, Robert,

thanks, but both examples don't even compile (the Parser throws XS9002 unexpected input ')').

What finally compiles is this (based on Roberts suggestion):

pBytes := BYTE[]{dwBufSize}
ACE.ADSGetRecord(hTbl, pBytes, @dwBufSize)
System.Runtime.InteropServices.Marshal.Copy( pBytes, 0, pR, dwBufSize )

I hope this what was meant :)
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