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Overview |
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Group |
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Quick Info
Windows NT
| Yes
| Win95
| Yes
| Win32s
| No
| Import Library
| -
| Header File
| cpl.h
| Unicode
| No
| Platform Notes
| None
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CPL_INQUIRE
The CPL_INQUIRE message is sent to the CPlApplet function of a Control Panel application to request information about a dialog
box that the application supports.
CPL_INQUIRE
uAppNum = (UINT) lParam1; // application number
lpcpli = (LPCPLINFO) lParam2; // structure for application info.
Parameters
uAppNum
Value of lParam1. Specifies the dialog box number. This number must be in the range zero
through one less than the value returned in response to the CPL_GETCOUNT message (CPL_GETCOUNT  1).
lpcpli
Value of lParam2. Points to a CPLINFO structure. The application must fill this structure with resource identifiers
for the icon, short name, description, and any user-defined value associated
with the dialog box.
Return Values
If the CPlApplet function processes this message successfully, it should return zero.
Remarks
The Control Panel sends the CPL_INQUIRE message once for each dialog box
supported by your application. The Control Panel also sends a CPL_NEWINQUIRE message for each dialog box. These messages are sent immediately after the CPL_GETCOUNT message. However, the system does not guarantee the order in which the
CPL_INQUIRE and CPL_NEWINQUIRE messages are sent.
You can perform initialization for the dialog box when you receive
CPL_INQUIRE. If you must allocate memory, do so in response to the CPL_INIT message.
On Windows 95 and Windows NT version 4.0, the system caches the information
returned in the CPLINFO structure used by CPL_INQUIRE. This provides significantly better performance
because the system only needs to load your application the first time the
Control Panel starts up. On the other hand, the CPL_NEWINQUIRE message returns
information in a form that the system cannot cache. For this reason, most CPlApplet functions should process CPL_INQUIRE and ignore CPL_NEWINQUIRE.
The only applications that should use CPL_NEWINQUIRE are those that need to
change their icon or display strings based on the state of the computer. In this
case, your CPL_INQUIRE handler should specify the CPL_DYNAMIC_RES value for the idIcon, idName, or idInfo members of the CPLINFO structure, rather than specifying a valid resource identifier. This causes
the Control Panel to send the CPL_NEWINQUIRE message each time it needs the icon
and display strings, allowing you to specify information based on the current
state of the computer. Of course, this is significantly slower than using cached
information.
See Also
CPL_GETCOUNT, CPL_INIT, CPL_NEWINQUIRE, CPlApplet, CPLINFO
Related Links
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Unix Manual Pages
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