| Call External and Win32 API dll's Subroutine calls [message #23374] |
Sat, 13 January 2001 18:59 |
muswick
Messages: 10
Registered: April 1998
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Junior Member |
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Maybe someone has solved these problems with calling standard Win32
api's without having to use a C-Wrapper routine. I search this
newsgroup and I have a few examples but none that seems to address
this problem directly.
There 3 examples below:
1: Calling a Win32 Subroutine with arguments
The problem is that no data is returned.
2: Calling a Win32 Function without arguments
No problem - This works (from this newsgroup)
3: Calling a Win32 Subrouting with arguments
The problem is an immediate crash.
Example 1
------------------------------------------------------------ -------
From Win32 API:
Public Declare Sub GetLocalTime Lib "kernel32" Alias "GetLocalTime"
(lpSystemTime As SYSTEMTIME)
Public Type SYSTEMTIME
wYear As Integer
wMonth As Integer
wDayOfWeek As Integer
wDay As Integer
wHour As Integer
wMinute As Integer
wSecond As Integer
wMilliseconds As Integer
End Type
Here is the IDL code I have tried:
timedata = INTARR(8)
timedata2 = BYTARR(16)
SYSTEMTIME = { $
wYear : 0, $
wMonth : 0, $
wDayOfWeek : 0, $
wDay : 0, $
wHour : 0, $
wMinute : 0, $
wSecond : 0, $
wMilliseconds : 0}
result = CALL_EXTERNAL('kernel32.dll','GetLocalTime',timedata)
help,result
print,timedata
result = CALL_EXTERNAL('kernel32.dll','GetLocalTime',timedata2)
help,result
print,timedata2
result = CALL_EXTERNAL('kernel32.dll','GetLocalTime',systemtime)
help,result
print,systemtime
RESULT LONG = 0
0 0 0 0 0 0 0 0
RESULT LONG = 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
RESULT LONG = 0
{ 0 0 0 0 0 0 0 0}
Example 2
------------------------------------------------------------ -------
Now a Win32 API function call with no arguments works:
From Win32 API:
Public Declare Function GetLogicalDrives Lib "kernel32" Alias
"GetLogicalDrives" () As Long
The IDL code:
drivemask=CALL_EXTERNAL('kernel32.dll','GetLogicalDrives')
help,drivemask
DRIVEMASK LONG = 125
Example 3
------------------------------------------------------------ -------
From Win32 API:
Public Declare Sub GetSystemInfo Lib "kernel32" Alias "GetSystemInfo"
(lpSystemInfo As SYSTEM_INFO)
Public Type SYSTEM_INFO
dwOemID As Long
dwPageSize As Long
lpMinimumApplicationAddress As Long
lpMaximumApplicationAddress As Long
dwActiveProcessorMask As Long
dwNumberOrfProcessors As Long
dwProcessorType As Long
dwAllocationGranularity As Long
dwReserved As Long
End Type
The IDL code:
sysinfo = {SYSTEM_INFO, $
dwOemID : 0L, $
dwPageSize : 0L, $
lpMinimumApplicationAddress : 0L, $
lpMaximumApplicationAddress : 0L, $
dwActiveProcessorMask : 0L, $
dwNumberOrfProcessors : 0L, $
dwProcessorType : 0L, $
dwAllocationGranularity : 0L, $
dwReserved : 0L}
result = CALL_EXTERNAL('kernel32.dll','GetSystemInfo',sysinfo)
help,result
print,sysinfo
Causes an immediate Page Fault and crash of IDL.
------------------------------------------------------------ -------
I am most likely applying the arguments wrong. I am positive that
I could get the above to work using a C-wrapper with (argc, argv)
calling, but there are reasons that I would perfer not to go this
route.
Any help would appreciated.
Gary Muswick
muswick@uhrad.com
216 844-7793
Sent via Deja.com
http://www.deja.com/
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