# Using the function reference

This section provides an alphabetical reference to the MSPP API functions. A prototype of each function is shown with the function description and details of all its arguments and return values. A typical function includes:

Prototype | The prototype is followed by a listing of the function's arguments. Dialogic data types include: WORD (16-bit unsigned) DWORD (32-bit unsigned) INT16 (16-bit signed) INT32 (32-bit signed) BYTE (8-bit unsigned) If a function argument is a data structure, the complete data structure is shown.
Return values | The return value for a function is either SUCCESS or an error code. For asynchronous functions, a return value of SUCCESS indicates the function was initiated; subsequent events indicate the status of the operation. Refer to the Alphabetical error summary for a listing of all errors returned by MSPP functions.
Events | If events are listed, the function is asynchronous and is complete when the DONE event is returned. If there are no events listed, the function is synchronous. Additional information such as reason codes and return values may be provided in the value field of the event. Refer to MSPP events for information about MSPP events and reason codes.
Details | Additional information about the function.
See also | A list of related functions.
Example | Example functions taken from sample application programs shipped with the product. The notation /* ... */ indicates additional code that is not shown.

The MSPP API references the following header files:

Header file | Description
mspcmd.h | MSPP filter commands and IDs for each filter object.
mspdef.h | Functions, parameter structures, events, and errors within the MSPP API.
mspinit.h | Initialization parameters for MSPP endpoint and channel filters.
mspobj.h | MSPP objects. This file defines unique identifiers that applications may need to use to communicate with an object and identifies the MSPP service objects to which queries and messages are addressed.
mspquery.h | MSPP filter queries for MSPP objects. The file defines the return data structure for each query.
mspunsol.h | MSPP event IDs and definitions for buffers appended in unsolicited events.