Re: CreateProcessA Lib "kernel32" problem

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From: Randy Birch (rgb_removethis_at_mvps.org)
Date: 07/08/04 

Date: Thu, 8 Jul 2004 10:34:35 -0400

The VB viewer defines some variables as the data type expected, eg As String
or As SECURITY_ATTRIBUTES (a user-defined type). Others will declare those
members As Long and will pass a memory pointer to where the string or
SECURITY_ATTRIBUTES UDT exists. For strings one uses StrPtr(sTheString). For
SECURITY_ATTRIBUTES Byval 0& is often used to indicate no
SECURITY_ATTRIBUTES are being set, meaning use the current thread's security
settings. If you want to get technical, under the hood VB passes everything
as a Long value anyway representing the memory address of the particular
variable's contents. Therefore some declares are simply defined to accept
Long values anyway. 

-- 
Randy Birch
MVP Visual Basic
http://vbnet.mvps.org/
Please respond only to the newsgroups so all can benefit.
"vbVeryBeginner" <anonymous@anonymous.com> wrote in message 
news:40ecaa0c_2@news.tm.net.my...
: thanks first, zoury and gale green
:
: now, this is funny.
: i figure out how to did it but i don't really understand what going on.
: let say i am going to use the WIN32 API CreateProcess, the first step i 
will
: do is to search for that function using the VB provided API Viewer.
:
: it ask me to declare using the following statement
:
: 01>   Private Declare Function CreateProcess Lib "kernel32" Alias
: "CreateProcessA" ( _
: 02>      ByVal lpApplicationName As String, _
: 03>      ByVal lpCommandLine As String, _
: 04>      lpProcessAttributes As SECURITY_ATTRIBUTES, _
: 05>      lpThreadAttributes As SECURITY_ATTRIBUTES, _
: 06>      ByVal bInheritHandles As Long, _
: 07>      ByVal dwCreationFlags As Long, _
: 08>      lpEnvironment As Any, _
: 09>      ByVal lpCurrentDriectory As String, _
: 10>      lpStartupInfo As STARTUPINFO, _
: 11>      lpProcessInformation As PROCESS_INFORMATION) As Long
:
: and after much desperate tries to figure out what went wrong, i try
: downloading some other example code and to my astonishment, they use a
: DIFFERENT declaration!
:
: 01>   Private Declare Function CreateProcessA Lib "kernel32" ( _
: 02>      ByVal lpApplicationName As Long, _
: 03>      ByVal lpCommandLine As String, _
: 04>      ByVal lpProcessAttributes As Long, _
: 05>      ByVal lpThreadAttributes As Long, _
: 06>      ByVal bInheritHandles As Long, _
: 07>      ByVal dwCreationFlags As Long, _
: 08>      ByVal lpEnvironment As Long, _
: 09>      ByVal lpCurrentDirectory As Long, _
: 10>      lpStartupInfo As STARTUPINFO, _
: 11>      lpProcessInformation As PROCESS_INFORMATION) As Long
:
: the differences are
: #2
: ByVal lpApplicationName As String (VB API Declaration)
: ByVal lpApplicationName As Long (Their Declaration)
:
: #4
: lpProcessAttributes As SECURITY_ATTRIBUTES (VB)
: ByVal lpProcessAttributes As Long (Their)
:
: #5
: lpThreadAttributes As SECURITY_ATTRIBUTES (VB)
: ByVal lpThreadAttributes As Long (Their)
:
: #8
: lpEnvironment As Any (VB)
: ByVal lpEnvironment As Long (Their)
:
: #9
: ByVal lpCurrentDriectory As String (VB)
: ByVal lpCurrentDirectory As Long (Their)
:
: i have NO LUCK using the VB provided API Viewer but able to start the
: notepad.exe using THEIR declaration. now, why the VB declaration can't 
run!
: because i thought the VB API Viewer should be the official resource of API
: declaration. Should i trust the VB API Viewer anymore?
:
: i also have an PSDK august 2001 edition.
:
: BOOL CreateProcess(
:   LPCTSTR lpApplicationName,                 // name of executable module
:   LPTSTR lpCommandLine,                      // command line string
:   LPSECURITY_ATTRIBUTES lpProcessAttributes, // SD
:   LPSECURITY_ATTRIBUTES lpThreadAttributes,  // SD
:   BOOL bInheritHandles,                      // handle inheritance option
:   DWORD dwCreationFlags,                     // creation flags
:   LPVOID lpEnvironment,                      // new environment block
:   LPCTSTR lpCurrentDirectory,                // current directory name
:   LPSTARTUPINFO lpStartupInfo,               // startup information
:   LPPROCESS_INFORMATION lpProcessInformation // process information
: );
:
: according to this API, the declaration provided by the VB API Viewer 
SHOULD
: be correct, but WHY it can't runs ???
:
: as a vbVeryBeginner, i hope this won't discourage me...:)
: sincerely hope somebody here in NG would love to explain to me...WHY...
: thanks
:
:
:
:
:
:

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