SAE航空航天标准文件AS681是本SAE航空航天推荐实践（ARP）的父文件。AS681适用于按照本文件编写的发动机程序。该ARP指定了一组函数及其预期行为，这些函数及其预期行为构成了燃气涡轮发动机客户程序的基于函数的应用程序接口(API)。此API中指定的功能由供应商作为引擎模型的一部分交付。 本文档定义了C和Fortran中实现的通用语言独立函数和特定附录。 本ARP中指定的基于函数的API代表了AS4191中指定的Fortran公共块结构的替代方案，历史上用于与引擎程序通信。如果需要，客户可以请求模拟AS4191接口。本文档没有指定如何构造引擎程序中的参数名称，如何扩展或更改程序功能，或者如何构造错误消息。有关命名的总体指南，请参见AS6502。有关命名法、扩展程序操作能力以及为面向对象模型生成错误值和消息的信息，请参见ARP5571。

The SAE Aerospace Standard document AS681 is the parent document of this SAE Aerospace Recommended Practice (ARP). AS681 applies to Engine programs written to conform to this document. This ARP specifies a set of functions and their expected behaviors that constitute a function based Application Program Interface (API) for gas turbine engine customer programs. The functions specified in this API are delivered by the Supplier as part of the Engine model. This document defines generic language independent functions and specific appendices for implementations in C and Fortran. The function based API specified in this ARP represents an alternative to the Fortran COMMON block structure, as specified in AS4191, historically used to communicate with an engine program. The customer may request emulation of the AS4191 interface if desired. This document does not specify how the parameter names in the Engine program are constructed, how program capabilities might be expanded or altered, or how error messages are constructed. See AS6502 for overall guidelines for nomenclature. See ARP5571 for information on nomenclature, expanding program operational capabilities and generating error values and messages for object-oriented models.