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MbufHookFunction


See also
Availability
Available in MIL-Lite
Available in MIL

Available on Windows
Available on Linux

Available on Non-Matrox computer
Available on Matrox 4Sight-X
Available on Matrox 4Sight GP
Available on Matrox Supersight
function map Function map
Examples
MbufGetLine
MbufImport
Synopsis
Hook a function to a buffer event.
Syntax
void MbufHookFunction(
MIL_ID BufferId, //in
MIL_INT HookType, //in
MIL_BUF_HOOK_FUNCTION_PTR HookHandlerPtr, //in
void *UserDataPtr //in
)
Description

This function allows you to attach or detach a user-defined function to a specified buffer event (for example, a modification to the buffer's contents). Once a hook-handler function is defined and hooked to an event, it is automatically called when the event occurs.

You can hook more than one function to an event by making separate calls to MbufHookFunction() for each function that you want to hook. MIL automatically chains and keeps an internal list of all these hooked functions. When a function is hooked, this new function is added to the end of the list. When the event happens, all user-defined functions in the list will be executed in the same order that they were hooked to the event. You can also remove any function from the list; in this case, MIL preserves the order of the remaining functions in the list.

Note that this function reference has not been updated for a MIL system added during a MIL update. Refer to the MIL system's release note to see if there is complementary information.
Parameters
This function is not supported on the selected boards.
Parameters
BufferId

Specifies the identifier of the buffer.

HookType

Specifies the buffer event to which to hook the function. This parameter can be set to following value:

function map For specifying the buffer event
CollapseValue Description
Collapse M_MODIFIED_BUFFER +

Calls the hook-handler function each time the specified buffer is modified by a MIL function.
Combination constant for the values listed in For specifying the buffer event.

You can add the following value to the above-mentioned value to set whether to detach the hook-handler function.

function map For M_MODIFIED_BUFFER
CollapseCombination value Description
Collapse M_UNHOOK

Unhooks the specified function if hooked to an M_MODIFIED_BUFFER event.
HookHandlerPtr

Specifies the address of the function that should be called when the specified event occurs. The hook-handler function must be declared as follows:

Upon successful completion, the hook-handler function should return M_NULL. Note MFTYPE and MIL_BUF_HOOK_FUNCTION_PTR are reserved MIL predefined types for functions and data pointers.

MIL_INT MFTYPE HookHandler(
MIL_INT HookType,
MIL_ID EventId,
void *UserDataPtr
)
Parameters
HookType

Type of buffer event that generated the call.

EventId

Event identifier to pass to MbufGetHookInfo() when inquiring about the hooked event.

UserDataPtr

User data pointer that was passed (as UserDataPtr) to MbufHookFunction().

UserDataPtr

Specifies the address of the user data that you want to make available to the hook-handler function. This address is passed to the hook-handler function, through its UserDataPtr parameter, when the specified event occurs. Set this parameter to M_NULL if not used.

Compilation information
Header Include mil.h.
Library Use mil.lib.
DLL Requires mil.dll.
MODIFIED BUFFER UNHOOK