Hello, I have wrapped a dll called shmdll.dll that encapsulates some Shared Memory routines and am trying to access it with Win32::API. I know about the Win32MemMap module but it seems to have a small memory leak in even the simplest cases. Anyway, I have two C routines:

int __export __stdcall SetSharedMem(const int shareIndex, const void* 
+lpszBuf, const DWORD bufLength)
int __export __stdcall GetSharedMem(const int shareIndex,void* lpszBuf
+, const DWORD bufLength)

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SetSharedMem writes what is passed in the variable lpszBuf (up to character bufLength) into a shared memory location referenced by shareIndex
GetSharedMem gets bufLength characters from that same shared memory location and puts it into lpszBuf

I have two corresponding Win32::API declarations:

$SetSharedMem = Win32::API->new('shmdll', 'int SetSharedMem(int shareI
+ndex, VOID* lpszBuf, DWORD bufLength)');
$GetSharedMem = Win32::API->new('shmdll', 'int GetSharedMem(int shareI
+ndex,VOID* lpszBuf, DWORD bufLength)');

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I don't seem to be having a problem setting the shared memory location but when I get the shared memory location using:

    $returnBuff = " " x ($str_length);<br>
    $return = $GetSharedMem->Call(0,$returnBuff,$str_length);<br><br>

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it seems to stop before first null character. I dumped (using Devel::Peek Dump command) the buffer when the shared memory is being set and what was returned. That looks like the following:

Setting:
SV = PV(0x1abed40) at 0x1dea898<br>
 REFCNT = 1<br>
 FLAGS = (POK,pPOK)<br>
 PV = 0x1dda434 "\4\4\0041234\4\4\4\10\3\2\0\0\0\n\r20\0asdfasdfaf\3\0
+\0\0Red\4
\2\1\0\0\0\n\01710|\0|Asdfasdfaf\4\0\0\0Blue"\0<br>
 CUR = 69<br>
 LEN = 70<br><br>

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Getting:
SV = PV(0x1abed64) at 0x1dea94c<br>
 REFCNT = 1<br>
 FLAGS = (POK,pPOK)<br>
 PV = 0x1dda218 "\4\4\0041234\4\4\4\10\3\2"\0<br>
 CUR = 13<br>
 LEN = 71<br><br>

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As you can see by the PV value it cuts off before the three nulls in a row. I am using a memcpy in the GetSharedMemory routine like:

memcpy(lpszBuf,tempShmEntry.shmLpMapAddress,bufLength); {where tempShmEntry.shmLpMapAddress is the address of the base of the buffer}

I have written the information in lpszBuf to a file from the C dll and it is all there. There seems to be a problem between C an Perl however. Does anyone have any ideas?
Thanks in advance,
Mike

20040204 Edit by Corion Added code tags

In reply to Problems Passing String Argument With Nulls From C To Perl by Anonymous Monk

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