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SetStatusBackFunction

Description

Registers the callback function called when a change in the printer status is detected.

Syntax

  
    INT SetStatusBackFunction( INT i_hdl, INT ( CALLBACK EXPORT *lpStatusCB ) ( DWORD o_st ) )

Parameter

i_hdl

API handle
Specify the API handle retrieved by OpenMonPrinter.

lpStatusCB

Callback function address
Specify the address of an application-defined callback function that receives the printer status.
When NULL is specified, monitoring of the printer status is canceled.

o_st

Printer status variable
Specify the variable in which the printer status is stored.

Return value

On success: Returns 0.
On failure: Returns an error code. See "Error Code List" for details of the error code.

Remarks

    • When a callback function is registered by this API, the callback function is called with the current printer status.
    • Even when the printer status is received, the callback function will not be called when the printer status has not changed from when it was last received.
    • When reconnection to the printer is detected, the printer status is the status received last at the time
    • When this API is called in the state that the callback function is registered, the already registered function becomes disabled, and a new callback function is registered.
    • Even when this API is called specifying the already registered and enabled callback function again, the printer status response immediately after it is performed.
    • The callback function registered by this API is unregistered by the following APIs:
      • CloseMonPrinter
      • CancelStatusBack
    • The following APIs cannot be called from the registered callback function with the same API handle:
      • CloseMonPrinter
      • SetStatusBackFunction
      • SetStatusBackWnd
      • CancelStatusBack
    • The return value of the callback function is ignored.
    • The time from receiving the printer status until calling the callback function is not guaranteed.
    • See "Printer Status List" for details of the printer status.