PC MAPI: C Equivalent to MAPI APPEXEC.TXT in MS Visual Basic

The information in this article applies to:

• Microsoft Mail for Windows, versions 3.0, 3.0b, and 3.2

SUMMARY

The Microsoft C code fragment below shows how to call application programming interface (API) functions in the APPEXEC.DLL file, which is included on the version 3.0 and 3.2 Microsoft Mail for PC Networks Technical Reference disk, to access the information in the PARAMBLK structure. The APPEXEC.TXT file, which is also included on the Microsoft Mail for PC Networks Technical Reference disk, includes only Microsoft Visual Basic code that calls APPEXEC.DLL.

The steps below describe how to access the PARAMBLK structure. This is also described in the APPEXEC.TXT file. After obtaining the MessageID returned by GetMessageID(), you can use Messaging API (MAPI) from versions 3.0 and 3.2 of Microsoft Mail for PC Networks to access information on the mail message correlating to the MessageID. This program was written using Microsoft Visual C++ version 1.0.

MORE INFORMATION

The code below shows that to access the PARAMBLK structure, your code must do the following:

1. Obtain the hexadecimal memory handle from the command line of your application.

2. Convert the hexadecimal handle into an integer.

3. Call the Windows API GlobalRealloc() function to copy the PARAMBLK structure into your application's memory.

4. Call the APPEXEC API ReleaseSemaphore() function to tell APPEXEC you have copied the PARAMBLK structure.

5. Call the APPEXEC API CrackParameterBlock() and GetMessageID() functions to obtain the wCommand and MessageID information from the PARAMBLK structure.

Sample Code Fragment

#include <windows.h>
#include <stdlib.h>
#include <appexec.h>

int PASCAL WinMain( HINSTANCE hinstCurrent, HINSTANCE hinstPrevious,

char    szBuf[ 128 ];
char    szHandle[ 128 ];
DWORD   dw;
BOOL    fVal;

// procedure to pull messageID

 wsprintf( szHandle, "0x%s", lpCmdLine );

 ghParamBlk = (HGLOBAL)strtol( szHandle, '\0', 16 );

 ghParamBlk = GlobalReAlloc( ghParamBlk, 0, GMEM_MODIFY |GMEM_MOVEABLE
      | GMEM_SHARE );

 ReleaseSemaphore();

 fVal = CrackParameterBlock( ghParamBlk, CPB_wCommand, &dw, szBuf );
 if( fVal == 0 )
   goto ErrorStarting;

 fVal = CrackParameterBlock( ghParamBlk, CPB_wMessageIDCount, &dw,
 szBuf);
 if( fVal == 0 || dw != 1 )
   goto ErrorStarting;

 fVal = GetMessageID( ghParamBlk, 0, szBuf );
 if( fVal == 0 )
    goto ErrorStarting;
                  }

else
 goto ErrorStarting;

ErrorStarting:

 MessageBox( 0, "Unable to get Message ID", "Error", MB_OK );
 return 1;