KbdOpen: Difference between revisions

Revision as of 02:45, 5 December 2016

Description

This call creates a new logical keyboard.

Syntax

KbdOpen (KbdHandle)

Parameters

KbdHandle (PHKBD) - output: Address of the logical keyboard.

Return Code

rc (USHORT) - return

Return code descriptions are:

0 NO_ERROR
440 ERROR_KBD_NO_MORE_HANDLE
441 ERROR_KBD_CANNOT_CREATE_KCB
464 ERROR_KBD_DETACHED
504 ERROR_KBD_EXTENDED_SG

Remarks

KbdOpen blocks while another thread has the keyboard focus (by way of KbdGetFocus) until the thread with the focus issues KbdFreeFocus. Therefore, to prevent KbdOpen from blocking, it is recommended that KbdOpen be issued only while the current thread has the focus. For example:

KbdGetFocus: wait until focus available on handle 0
KbdOpen: get a logical keyboard handle
KbdOpen: get another logical keyboard handle
KbdOpen: get yet another logical keyboard handle
KbdFreeFocus: give up the focus on handle 0.

Example Code

C Binding

#define INCL_KBD

USHORT  rc = KbdOpen(KbdHandle);

PHKBD            KbdHandle;     /* Keyboard handle */

USHORT           rc;            /* return code */

MASM Binding

EXTRN  KbdOpen:FAR
INCL_KBD            EQU 1

PUSH@  WORD    KbdHandle     ;Keyboard handle
CALL   KbdOpen

Returns WORD

@@ Line 3: / Line 3: @@
 ==Syntax==
-<PRE>
+  KbdOpen (KbdHandle)
-  KbdOpen
-    (KbdHandle)
-</PRE>
 ==Parameters==
 ; KbdHandle (PHKBD) - output : Address of the logical keyboard.
 ==Return Code==
   rc (USHORT) - return
 Return code descriptions are:
+* 0     NO_ERROR
-* 0     NO_ERROR
 * 440        ERROR_KBD_NO_MORE_HANDLE
 * 441        ERROR_KBD_CANNOT_CREATE_KCB
 * 464        ERROR_KBD_DETACHED
 * 504        ERROR_KBD_EXTENDED_SG
 ==Remarks==
 KbdOpen blocks while another thread has the keyboard focus (by way of KbdGetFocus) until the thread with the focus issues KbdFreeFocus. Therefore, to prevent KbdOpen from blocking, it is recommended that KbdOpen be issued only while the current thread has the focus. For example:
 ; KbdGetFocus : wait until focus available on handle 0
+; KbdOpen : get a logical keyboard handle
-; KbdOpen : get a logical keyboard handle
+; KbdOpen : get another logical keyboard handle
+; KbdOpen : get yet another logical keyboard handle
-; KbdOpen : get another logical keyboard handle
+; KbdFreeFocus : give up the focus on handle 0.
-; KbdOpen : get yet another logical keyboard handle
-; KbdFreeFocus : give up the focus on handle 0.
 ==Example Code==
@@ Line 57: / Line 49: @@
 </PRE>
-==Related Functions==
+[[Category:Kbd]]
-*
-[[Category:The OS/2 API Project]]