WinQueryWindowDC: Difference between revisions
Created page with " This function returns the device context for a given window. ==Syntax== WinQueryWindowDC(hwnd) ==Parameters== ;hwnd (HWND) - input :Window handle. ==Returns== ;hdc (HDC..." |
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This function returns the device context for a given window. | |||
==Syntax== | ==Syntax== | ||
WinQueryWindowDC(hwnd) | WinQueryWindowDC(hwnd) | ||
==Parameters== | ==Parameters== | ||
;hwnd (HWND) - input | ;hwnd (HWND) - input:Window handle. | ||
:Window handle. | |||
==Returns== | ==Returns== | ||
;hdc (HDC) - returns | ;hdc (HDC) - returns:Device-context handle. | ||
:Device-context handle. | ::NULLHANDLE - Either WinOpenWindowDC has not been called for this window, or an error has occurred. | ||
: | ::Other - Device context handle. | ||
: | |||
==Errors== | ==Errors== | ||
Possible returns from WinGetLastError | Possible returns from WinGetLastError | ||
::PMERR_INVALID_HWND (0x1001) :An invalid window handle was specified. | |||
:An invalid window handle was specified. | |||
==Remarks== | ==Remarks== | ||
A handle is returned only if a device context has been opened for the window with WinOpenWindowDC. | A handle is returned only if a device context has been opened for the window with [[WinOpenWindowDC]]. | ||
==Example Code== | ==Example Code== | ||
This example shows how to check if WinOpenWindowDC has been called for this window. | This example shows how to check if WinOpenWindowDC has been called for this window. | ||
<pre> | <pre> | ||
#define INCL_WINWINDOWMGR | #define INCL_WINWINDOWMGR | ||
#include < | #include <os2.h> | ||
HWND hwndClient; /* window handle. */ | HWND hwndClient; /* window handle. */ | ||
| Line 35: | Line 31: | ||
/* ... */ | /* ... */ | ||
} | } | ||
</pre> | </pre> | ||
==Related Functions== | ==Related Functions== | ||
* WinEnableWindow | * [[WinEnableWindow]] | ||
* WinIsThreadActive | * [[WinIsThreadActive]] | ||
* WinIsWindow | * [[WinIsWindow]] | ||
* WinIsWindowEnabled | * [[WinIsWindowEnabled]] | ||
* WinQueryDesktopWindow | * [[WinQueryDesktopWindow]] | ||
* WinQueryObjectWindow | * [[WinQueryObjectWindow]] | ||
* WinQueryWindowProcess | * [[WinQueryWindowProcess]] | ||
* WinQueryWindowRect | * [[WinQueryWindowRect]] | ||
* WinWindowFromDC | * [[WinWindowFromDC]] | ||
* WinWindowFromID | * [[WinWindowFromID]] | ||
* WinWindowFromPoint | * [[WinWindowFromPoint]] | ||
[[Category:Win]] | [[Category:Win]] | ||
Latest revision as of 18:39, 14 May 2025
This function returns the device context for a given window.
Syntax
WinQueryWindowDC(hwnd)
Parameters
- hwnd (HWND) - input
- Window handle.
Returns
- hdc (HDC) - returns
- Device-context handle.
- NULLHANDLE - Either WinOpenWindowDC has not been called for this window, or an error has occurred.
- Other - Device context handle.
Errors
Possible returns from WinGetLastError
- PMERR_INVALID_HWND (0x1001) :An invalid window handle was specified.
Remarks
A handle is returned only if a device context has been opened for the window with WinOpenWindowDC.
Example Code
This example shows how to check if WinOpenWindowDC has been called for this window.
#define INCL_WINWINDOWMGR
#include <os2.h>
HWND hwndClient; /* window handle. */
if(WinQueryWindowDC(hwndClient))
{
/* ... */
}