PFAX_SEND_CALLBACK callback function (faxdev.h)

Article
02/22/2024

The FaxSendCallback function is an application-defined or library-defined callback function that a fax service provider (FSP) calls to notify the fax service that an outgoing fax call is in progress.

The PFAX_SEND_CALLBACK data type is a pointer to a FaxSendCallback function. FaxSendCallback is a placeholder for an application-defined or library-defined function name.

Syntax

PFAX_SEND_CALLBACK PfaxSendCallback;

BOOL PfaxSendCallback(
  [in] HANDLE FaxHandle,
  [in] HCALL CallHandle,
  [in] DWORD Reserved1,
  [in] DWORD Reserved2
)
{...}

Parameters

[in] FaxHandle

Type: HANDLE

Specifies a fax handle returned by the FaxDevStartJob function.

[in] CallHandle

Type: HCALL

Specifies a call handle returned by the TAPI 2.x LINE_CALLSTATE message.

[in] Reserved1

Type: DWORD

This parameter is reserved for future use by Microsoft. It must be set to zero.

[in] Reserved2

Type: DWORD

This parameter is reserved for future use by Microsoft. It must be set to zero.

Return value

Type: BOOL

The fax service returns a value of TRUE to indicate that the active fax operation should continue.

The fax service returns a value of FALSE to indicate that the active fax operation should be terminated. To get extended error information, call GetLastError.

Remarks

The FaxSendCallback callback function provides the fax service with the CallHandle that TAPI assigns. This handle is necessary for TAPI message routing. If the FSP does not call FaxSendCallback, it will miss all further call events.

A virtual FSP does not need the FaxSendCallback function.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional, Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	faxdev.h