The values of the wParam and lParam parameters depend on the hook code, but they typically contain information about a message that was sent or posted. The value of the hook code depends on the type of the hook each type has its own characteristic set of hook codes. The nCode parameter is a hook code that the hook procedure uses to determine the action to perform. HookProc is a placeholder for an application-defined name. Return CallNextHookEx(NULL, nCode, wParam, lParam) A hook procedure must have the following syntax: LRESULT CALLBACK HookProc(
#Hooking up and using nuendo 5 install
To take advantage of a particular type of hook, the developer provides a hook procedure and uses the SetWindowsHookEx function to install it into the chain associated with the hook. The hook procedures for some types of hooks can only monitor messages others can modify messages or stop their progress through the chain, preventing them from reaching the next hook procedure or the destination window. The action a hook procedure can take depends on the type of hook involved. When a message occurs that is associated with a particular type of hook, the system passes the message to each hook procedure referenced in the hook chain, one after the other. A hook chain is a list of pointers to special, application-defined callback functions called hook procedures. The system maintains a separate hook chain for each type of hook. For example, an application can use the WH_MOUSE hook to monitor the message traffic for mouse messages. The system supports many different types of hooks each type provides access to a different aspect of its message-handling mechanism. You should install a hook only when necessary, and remove it as soon as possible. Hooks tend to slow down the system because they increase the amount of processing the system must perform for each message.