参考 C11standard(ISO/IEC9899:2011):6.3Conversions(p:50-56)C99standard(ISO/IEC9899:1999):6.3Conversions(
Implicit conversions
Conversions Iftheoperandpassedtoanarithmeticoperatorisintegralorunscopedenumerationtype,thenbeforeanyotheraction
(SomeexperimentalapplicationsofContent-TypeforInternetmailhaveusedamedia-typeparameterof";conversions
(Internet邮件的Content-Type的一些实验性应用程序使用媒体类型参数“;conversions=<content-coding>”来执行等同于Content-Encoding的功能,但该参数不是