2 Normative references [intro.refs]

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document.
For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any amendments) applies.
The library described in Clause 7 of ISO/IEC 9899:2018 is hereinafter called the C standard library.1
The operating system interface described in ISO/IEC 9945:2003 is hereinafter called POSIX.
The ECMAScript Language Specification described in Standard Ecma-262 is hereinafter called ECMA-262.
References to ISO/IEC 10646-1:1993 are used only to support deprecated features ([depr.locale.stdcvt]).
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With the qualifications noted in [support] through [thread] and in [diff.library], the C standard library is a subset of the C++ standard library.