Writing to STDOUT from PBDLL6

[Paul Noble]

Hello all,

The following PBDLL6 snippet should (or so I thought) write a text string if you run it
from a DOS window under Windows (98) -

'
'Write a simple string to STDOUT
'
#compile   exe
#dim       all
#register  none
#include   "c:\pbdll6\winapi\win32api.inc"

function pbmain() as long

	dim mBytes   as long
	dim sText    as asciiz * 10

	sText = "Hello"
	WriteFile GetStdHandle(%STD_OUTPUT_HANDLE), sText, Len(sText), mBytes, ByVal %NULL

	msgbox "Wrote " & format$(mBytes) & " bytes"

end function

Unfortunately it doesn't write anything, and just says 'Wrote 0 bytes'. Well, at least that
bit works . Can anyone show me where I'm going wrong ?

Thanks in advance -

Paul

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[Semen Matusovski]

Add AllocConsole

#Compile   Exe
#Dim       All
#Register  None
#Include   "win32api.inc"
Function PbMain() As Long
   Dim mBytes   As Long
   Dim sText    As Asciiz * 10
   AllocConsole
   sText = "Hello"
   WriteFile GetStdHandle(%STD_OUTPUT_HANDLE), sText, Len(sText), mBytes, ByVal %NULL
   MsgBox "Wrote " & Format$(mBytes) & " bytes"
End Function

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[Paul Noble]

Great, that's sorted it.

Thanks a bunch Semen -

Regards,

Paul

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[Edwin Knoppert]

+ use the 'mkcons' from my site..

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[email protected]

[Paul Noble]

Thanks Edwin, in fact I don't actually need to use a console... I had assumed that
if you were running a program from the command line in a DOS window, anything written
to STDOUT would appear in that window. Obviously not.

This came about because I was testing my first attempt at a CGI program, written with
PBDLL6. I had run PHP.EXE (ie: PHP4 as a CGI interpreter) with a file name argument
from the command line, and it did write the output to the DOS box. So although
my program now works well, I'm puzzled as to why it doesn't write its output to the
DOS window as the PHP interpreter does.

Paul

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[Semen Matusovski]

Paul --
Following code demonstrates, how PB/DLL module converts itself to console app.
Name Bas module, for example, "~Tmp.Bas" and start it in PB/DLL IDE.
Being started, module tests - there is console window or not.
If not, it cuts first symbol in Exe-Name (~Tmp.Exe -> Tmp.Exe), marks byte 221 as CHR$(3) - console app, and starts "release" version (Tmp.Exe).
If there is a wish to start a module in Dos Prompt, set %ExitToDosPrompt = %True.
In command prompt you can start an app by typing Tmp.

Note, that Tmp.Exe shares console window with command prompt.

   #Dim All
   #Compile Exe
   #Include "Win32Api.Inc"

   %ExitToDosPrompt = %False
   
   Sub ConvertToConsole
      Local Path As Asciiz * %MAX_PATH, i As Long, Tmp As String
      GetModuleFileName GetModuleHandle(ByVal 0&), Path, SizeOf(Path)
      i = Instr(-1, Path, "\")
      Open Path For Binary Shared As #1: Get$ #1, Lof(1), Tmp: Close #1
      Path = Left$(Path, i) + Mid$(Path, i + 2): Mid$(Tmp, 221, 1) = Chr$(3)
      Open Path For Output As #1: Print #1, Tmp;: Close #1
      $If %ExitToDosPrompt
      i = Shell("Command.com")
      $Else
      i = Shell(Chr$(34) + Path + Chr$(34) + " " + Command$)
      $EndIf
   End Sub
   
   Global hConsoleOutput As Long, hConsoleInput As Long
   
   Function PbMain
      hConsoleOutput = GetStdHandle(%STD_OUTPUT_HANDLE)
      If hConsoleOutput = 0 Then ConvertToConsole: Exit Function ' From IDE
      hConsoleOutput = GetStdHandle(%STD_OUTPUT_HANDLE)
      hConsoleInput  = GetStdHandle(%STD_INPUT_HANDLE)
      SetConsoleMode hConsoleInput, %NULL

      Dim mBytes As Long
      Dim sText As Asciiz * 10
      sText = "Hello"
      WriteFile GetStdHandle(%STD_OUTPUT_HANDLE), sText, Len(sText), mBytes, ByVal %NULL
      MsgBox "Wrote " & Format$(mBytes) & " bytes"
   End Function

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[Paul Noble]

Semen,

Thanks very much, I follow that, and it now works perfectly.

It was necessary to change one line though -

  If hConsoleOutput = %INVALID_HANDLE_VALUE Then ConvertToConsole: Exit Function ' From IDE

instead of

  If hConsoleOutput = 0...

Thanks again -

Regards,

Paul


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[Semen Matusovski]

Paul --
> If hConsoleOutput = %INVALID_HANDLE_VALUE Then
Not agree, at least, for Win2000.
%INVALID_HANDLE_VALUE = -1
Win2000 returns 0.
About which OS do you talk ?


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[Paul Noble]

Semen,

Interesting. I'm using Win98SE. When run from the IDE, the ~Tmp.exe code always returns -1
(%INVALID_HANDLE_VALUE) on my machine for hConsoleOutput.

I wonder if they have redefined INVALID_HANDLE_VALUE under Win2000, or whether GetStdHandle()
is simply behaving differently ?



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[Semen Matusovski]

Hmm ...
I can speculate only.
hStdInput and hStdOutput and parts of STARTUPINFO structure.
Explorer can use CreateProcess or ShellExecute.
If CreateProcess - different Explorer.Exe are able to fill these fields by different way.
If ShellExecute - different code for 9x & NT.

So, it's necessary to test results under other OSes and to make double test in program (<= 0)




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[Eric Pearson]

Semen --

> (<= 0)

Not all negative handle values are invalid! If you use a LONG to store a handle, you will encounter many negative values.

Invalid handle values include -1, 0, and the DWORD equivalent of -1, which is &hFFFFFFFF???.

-- Eric

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Perfect Sync: Perfect Sync Development Tools
Email: mailto:[email protected][email protected]</A>

[Semen Matusovski]

Eric --
If to talk about handles in general - agree, because hBmp, for example, is address in virtual memory.
But what means hFile ? It looks like order no.



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[Lance Edmonds]

(Semen, these comments are not aimed at you, but rather at the others that lurk here).

It would be unwise to "assume" that file handles are in some type of sequence or could be an index into a table, or will always be signed (positive) values...

ie, Microsoft could revise that behavior in a flash, and any application that makes assumptions on these values could be leaving themselves open to compatibility issues.

IOW, it is irrelevent what that actual value of a file handle is, as long as you store the value correctly, and use care when comparing API return values...

------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>