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DECLARE AND DATA TYPES
January 2024
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CCB
1. THE DECLARE STATEMENT SYNTAX (from dv_foxhelp9.chm):
DECLARE [cFunctionType] FunctionName IN LibraryName [AS AliasName]
[cParamType1 [@] ParamName1, cParamType2 [@] ParamName2, ...]
cFunctionType
Indicates the data type of the return value from the shared library, if any.
If the function does not return a value, omit cFunctionType.
cFunctionType can assume the following values:
SHORT 16-bit integer
INTEGER 32-bit integer
SINGLE 32-bit floating point
DOUBLE 64-bit floating point
LONG 32-bit long integer
STRING Character string
OBJECT IDispatch object type
2. REFERENCE CODE:
Usually, VFP Advanced (x64) supports all above function types same as VFP 9.0.
When we pass a structure data as string to the windows api function,
we MUST pass the 64-bit structure data instead of the 32-bit structure data.
For example,
BOOL ShellExecuteEx(
_Inout_ SHELLEXECUTEINFO *pExecInfo
);
When we pass the SHELLEXECUTEINFO structure data to ShellExecuteEx,
we MUST pass the 64-bit SHELLEXECUTEINFO structure data.
The 32-bit SHELLEXECUTEINFO structure:
typedef struct _SHELLEXECUTEINFO {
DWORD cbSize; // 0x00, cbSize = 0x3C
ULONG fMask; // 0x04
HWND hwnd; // 0x08
LPCTSTR lpVerb; // 0x0C
LPCTSTR lpFile; // 0x10
LPCTSTR lpParameters; // 0x14
LPCTSTR lpDirectory; // 0x18
int nShow; // 0x1C
HINSTANCE hInstApp; // 0x20
LPVOID lpIDList; // 0x24
LPCTSTR lpClass; // 0x28
HKEY hkeyClass; // 0x2C
DWORD dwHotKey; // 0x30
HANDLE hIcon; // 0x34
HANDLE hProcess; // 0x38
} SHELLEXECUTEINFO, *LPSHELLEXECUTEINFO;
The size of 32-bit SHELLEXECUTEINFO structure data is 0x3C bytes.
The 64-bit SHELLEXECUTEINFO structure:
typedef struct _SHELLEXECUTEINFO {
DWORD cbSize; // 0x00, cbSize = 0x70
ULONG fMask; // 0x04
HWND hwnd; // 0x08
LPCTSTR lpVerb; // 0x10
LPCTSTR lpFile; // 0x18
LPCTSTR lpParameters; // 0x20
LPCTSTR lpDirectory; // 0x28
int nShow; // 0x30
DWORD padding1; // 0x34
HINSTANCE hInstApp; // 0x38
LPVOID lpIDList; // 0x40
LPCTSTR lpClass; // 0x48
HKEY hkeyClass; // 0x50
DWORD dwHotKey; // 0x58
DWORD padding2; // 0x5C
HANDLE hIcon; // 0x60
HANDLE hProcess; // 0x68
} SHELLEXECUTEINFO, *LPSHELLEXECUTEINFO;
The size of 64-bit SHELLEXECUTEINFO structure data is 0x70 bytes.
If we want the same code can run in VFP Advanced (x64) and VFP 9.0,
we can use the system variable _WIN64 to do it.
The system variable _WIN64 always returns true (.T.) in VFP Advanced 64-bit version.
For example,
PRIVATE m.q_execinfo
IF TYPE("_win64")="L".AND._win64=.T.
m.q_execinfo=;
fval2str(m.q_execinfo_cbsize,4)+;
fval2str(m.q_execinfo_fmask,4)+;
fval2str(m.q_execinfo_hwnd,8)+;
fval2str(m.q_execinfo_lpverb,8)+;
fval2str(m.q_execinfo_lpfile,8)+;
fval2str(m.q_execinfo_lpparameters,8)+;
fval2str(m.q_execinfo_lpdirectory,8)+;
fval2str(m.q_execinfo_nshow,4)+;
fval2str(0,4)+;
fval2str(m.q_execinfo_hinstapp,8)+;
fval2str(m.q_execinfo_lpidlist,8)+;
fval2str(m.q_execinfo_lpclass,8)+;
fval2str(m.q_execinfo_hkeyclass,8)+;
fval2str(m.q_execinfo_dwhotkey,4)+;
fval2str(0,4)+;
fval2str(m.q_execinfo_hicon,8)+;
fval2str(m.q_execinfo_hprocess,8)
ELSE
m.q_execinfo=;
fval2str(m.q_execinfo_cbsize,4)+;
fval2str(m.q_execinfo_fmask,4)+;
fval2str(m.q_execinfo_hwnd,4)+;
fval2str(m.q_execinfo_lpverb,4)+;
fval2str(m.q_execinfo_lpfile,4)+;
fval2str(m.q_execinfo_lpparameters,4)+;
fval2str(m.q_execinfo_lpdirectory,4)+;
fval2str(m.q_execinfo_nshow,4)+;
fval2str(m.q_execinfo_hinstapp,4)+;
fval2str(m.q_execinfo_lpidlist,4)+;
fval2str(m.q_execinfo_lpclass,4)+;
fval2str(m.q_execinfo_hkeyclass,4)+;
fval2str(m.q_execinfo_dwhotkey,4)+;
fval2str(m.q_execinfo_hicon,4)+;
fval2str(m.q_execinfo_hprocess,4)
ENDIF
=shellexecuteex(@m.q_execinfo)
In the header file, we can use the function SYS(17) instead of the system variable _WIN64.
For example,
* MSXML DOM parser
#IF SYS(17) = "X64"
#define MSXML_PARSER "MSXML2.DOMDocument.6.0"
#ELSE
#define MSXML_PARSER "MSXML2.DOMDocument.4.0"
#ENDIF
3. THE INTEGER AND LONG DATA TYPES:
In VFP 9.0 (and before), there is no difference for the INTEGER data type and the LONG data type, they are 32-bit integer.
In VFP Advanced (x64), for the HANDLE data type and the size_t data type, recommend to use the LONG data type instead of the INTEGER data type.
For example,
BOOL WINAPI OpenProcessToken(
_In_ HANDLE ProcessHandle,
_In_ DWORD DesiredAccess,
_Out_ PHANDLE TokenHandle
);
Sometimes the following code can not run fine in VFP Advanced (x64):
DECLARE INTEGER OpenProcessToken IN win32api ;
INTEGER ProcessHandle,;
INTEGER DesiredAccess,;
INTEGER @TokenHandle
Recommend to use the following code:
DECLARE INTEGER OpenProcessToken IN win32api ;
LONG ProcessHandle,;
INTEGER DesiredAccess,;
LONG @TokenHandle
4. REFERENCE WEBSITES:
For the HANDLE data type, usually it starts with the character H, for example, HANDLE, HBITMAP, HBRUSH.
Please refer to:
1, Windows Data Types.
http://msdn.microsoft.com/en-us/library/windows/desktop/aa383751(v=vs.85).aspx
5. OTHER:
For reference only, there is no guarantees.
Any questions or suggestions, please send me an email at ccb2000@163.com.
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