PRINTDLG and GDI object count?

[Semen Matusovski]

Funny ... Win2000, SP1. I removed all printers. Appears simple dialog - "add printers before".
On my PC PrintDlg eats 25 (- 1) objects in any case - there are printers or not.
Looks like clean program mistake - very doubt that these GDI objects are used in dialogs.

Time to push Bill or to write own PrintDlg .

One thought - if OS sees GDI objects (and they should be "free"), may be it's possible to enumerate GDI objects (interesting, how) and to delete them ?





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[Lance Edmonds]

Hi folks,

While researching a memory leak in an application, I found that the PrintDLG() creates over 20 GDI objects, and while these are not recreated with subsequent calls to PrintDLG(), these handles are not released until the app terminates.

So, I started to consider what would happen when this API was used in a separate thread... how much of a 'leak' would occur?

As a result, I wrote the following test code and ran it. It creates 5 PRINTDLG Dialog boxes, and displays a MSGBOX. While the MSGBOX was open I used Task Manager to look at the GDI count.

The results are not 100% consistent, but at it's worst, the app had 119 GDI objects allocated! As I closed each Dialog, the GDI count dropped only by one object.

Anyone got any ideas how to "flush" these objects?

#COMPILE EXE
#INCLUDE "comdlg32.inc"
 
FUNCTION T1(BYVAL z AS LONG) AS LONG
    DIM PD AS PRINTDLGAPI
    PD.lStructSize   = SIZEOF(PD)
    IF PrintDlg(PD) THEN
        IF PD.hDevMode  THEN GlobalFree PD.hDevMode
        IF PD.hDevNames THEN GlobalFree PD.hDevNames
    END IF
END FUNCTION
 
FUNCTION PBMAIN
    FOR x& = 1 TO 5
        THREAD CREATE T1(x&) TO Result&
        THREAD CLOSE Result& TO Result&
    NEXT x&
    MSGBOX "How many ?" ' while this is displayed, test for GDI objects in TaskMan.
END FUNCTION

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