Using Win32 functions in Visual FoxPro Image Gallery
Handle and Object
..msdn
CloseHandle
DuplicateHandle
GetHandleInformation
SetHandleInformation
Code examples:
Comparing file times
Copying files as a transacted operation (Vista)
Creating a console window for Visual FoxPro application
Creating a file, then moving it to another destination
Creating a mailslot
Enumerating Processes -- Win9*
Enumerating Processes -- WinNT
How to check whether the system is 32-bit or 64-bit
How to convert a bitmap file to monochrome format (1 bpp)
How to enable the SE_SHUTDOWN_NAME privilege for the application
How to find when the application started
How to make application automatically close all documents it opened
How to prevent users from accessing the Windows Desktop and from switching to other applications
How to run FoxPro application under different user name (impersonating user)
How to set Creation Date/Time for a folder (WinNT)
How to Start a Process as Another User (NT/XP/2K)
How to suspend or hibernate your system
HOWTO: Use the Win32 API to Access File Dates and Times
Locking and unlocking file of a VFP table
Monitoring changes occurring within a directory
Moving shortcut to a specified position on the Windows Desktop
Obtaining I/O counts for the current process
Obtaining names and positions for shortcuts located on the Windows Desktop
Obtaining physical parameters for a drive: sectors, clusters, cylinders...
Passing data records between VFP applications via the Clipboard
Peer-to-peer LAN messenger built with Mailslot API functions
Reading and setting system access privileges for the current process
Reading and setting the priority class values for the current process and thread
Retrieving file information for the VFP executable running
Running MSDOS Shell as a child process with redirected input and output (smarter RUN command)
Setting the date and time that a file was created
Starting external program from VFP and waiting for its termination
Storing content of the Clipboard to a bitmap file
Storing screen shot of a form to bitmap file
Subclassing CommandButton control to create BackColor property
Terminating all running applications from a VFP program
Testing serial ports
Using File Mapping for enumerating files opened by Visual FoxPro
Using GetFileSize
Using InternetSetFilePointer when resuming interrupted download from the Internet
Using mailslots to send messages on the network
Using named pipes for interprocess communication
Using shared memory to exchange data between applications (processes)
Using the CreateFile
Using the DeleteFile
Using the Semaphore object
Using the Semaphore object to allow only one instance of VFP application running
Vertical Label control
Testing serial ports

User rating: 0/10 (0 votes)
Rate this code sample:
  • ~
More code examples    Listed functions    Add comment     W32 Constants      Translate this page Printer friendly version of this code sample
Before you begin:
Another example: Enumerating the ports that are available for printing on a specified server
DO decl

LOCAL nIndex, cPort
FOR nIndex=1 TO 8
    cPort = "COM" + TRANSFORM(nIndex)
    ? "Testing port " + m.cPort + ":", TestPort(m.cPort)
ENDFOR
* end of main

FUNCTION TestPort(cPort)
#DEFINE FILE_SHARE_READ   1
#DEFINE FILE_SHARE_WRITE  2
#DEFINE OPEN_EXISTING     3
#DEFINE GENERIC_READ      0x80000000
#DEFINE GENERIC_WRITE     0x40000000
#DEFINE FILE_FLAG_OVERLAPPED 0x40000000
#DEFINE INVALID_HANDLE_VALUE -1
#DEFINE FILE_ATTRIBUTE_NORMAL 128

    LOCAL hPort, lnErr

*    hPort = CreateFile(cPort, GENERIC_READ, 0,0,;
        OPEN_EXISTING, FILE_FLAG_OVERLAPPED, 0)

    hPort = CreateFile(cPort,;
        BITOR(GENERIC_READ,GENERIC_WRITE),;
        0,0, OPEN_EXISTING,;
        BITOR(FILE_FLAG_OVERLAPPED,FILE_ATTRIBUTE_NORMAL), 0)

    IF hPort = INVALID_HANDLE_VALUE
        lnErr = GetLastError()
        RETURN "Error " + TRANSFORM(lnErr) +;
            ". " + GetErrorMessage(lnErr)
    ELSE
        = CloseHandle(hPort)
        RETURN "Ok"
    ENDIF

PROCEDURE decl
    DECLARE INTEGER CreateFile IN kernel32;
        STRING lpFileName, INTEGER dwAccess, INTEGER dwShareMode,;
        INTEGER lpSecurityAttr, INTEGER dwCreationDisp,;
        INTEGER dwFlagsAndAttr, INTEGER hTemplateFile

    DECLARE INTEGER CloseHandle IN kernel32 INTEGER hObject
    DECLARE INTEGER GetLastError IN kernel32

    DECLARE INTEGER FormatMessage IN kernel32;
        INTEGER dwFlags, INTEGER lpSource, INTEGER dwMessageId,;
        INTEGER dwLanguageId, INTEGER @lpBuffer,;
        INTEGER nSize, INTEGER Arguments

    DECLARE RtlMoveMemory IN kernel32 As CopyMemory;
        STRING @Destination, INTEGER Source, INTEGER nLength

FUNCTION GetErrorMessage(lnErr)
#DEFINE FORMAT_MESSAGE_ALLOCATE_BUFFER 256
#DEFINE FORMAT_MESSAGE_FROM_SYSTEM     4096
#DEFINE FORMAT_MESSAGE_IGNORE_INSERTS  512

    LOCAL dwFlags, lpBuffer, lnLength, lpResult
    dwFlags = FORMAT_MESSAGE_ALLOCATE_BUFFER +;
        FORMAT_MESSAGE_FROM_SYSTEM + FORMAT_MESSAGE_IGNORE_INSERTS

    lpBuffer = 0
    lnLength = FormatMessage(dwFlags, 0, lnErr, 0, @lpBuffer, 0,0)
    IF lnLength <> 0
        lpResult = REPLI(Chr(0), 500)
        = CopyMemory (@lpResult, lpBuffer, lnLength)
        RETURN STRTRAN(LEFT(lpResult, lnLength), Chr(13)+Chr(10), "")
    ELSE
        RETURN "[]"
    ENDIF



User rating: 0/10 (0 votes)
Rate this code sample:
  • ~
2151 bytes  
Created: 2002-05-06 20:14:58  
Modified: 2004-08-17 21:56:29  
Visits in 7 days: 163  
Listed functions:
CloseHandle
CopyMemory
CreateFile
FormatMessage
GetLastError
Printer friendly API declarations
My comment:
In Windows all input/output ports are presented as files, so work with ports is performed through file functions like CreateFile, CloseHandle, ReadFile, ReadFileEx, WriteFile and WriteFileEx.

Code sample Get the owner of an NTFS file works with serial ports as well as with regular files.

Check this MSDN article "Serial Communications in Win32".

Check VB example Using CreateFile to Determine Available COM Ports on VBNet.
Word Index links for this example:
Translate this page:
  Spanish    Portuguese    German    French    Italian  
FreeTranslation.com offers instant, free translations of text or web pages.
User Contributed Notes:
There are no notes on this subject.


Copyright 2001-2014 News2News, Inc. Before reproducing or distributing any data from this site please ask for an approval from its owner. Unless otherwise specified, this page is for your personal and non-commercial use. The information on this page is presented AS IS, meaning that you may use it at your own risk. Microsoft Visual FoxPro and Windows are trade marks of Microsoft Corp. All other trademarks are the property of their respective owners. 

Privacy policy
Credits: PHP (4.4.9), an HTML-embedded scripting language, MySQL (5.1.68), the Open Source standard SQL database, AceHTML Freeware Version 4, freeware HTML Editor of choice.   Hosted by Korax Online Inc.
Google
Advertise here!