21 Metaprogramming library [meta]

21.3 Metaprogramming and type traits [type.traits]

21.3.8 Transformations between types [meta.trans]

21.3.8.4 Sign modifications [meta.trans.sign]

1
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The templates specified in Table 56 convert an integer type to its corresponding signed or unsigned type.
Table 56: Sign modifications [tab:meta.trans.sign]
Template
Comments
template<class T>
struct make_signed;
If T is a (possibly cv-qualified) signed integer type ([basic.fundamental]) then the member typedef type denotes T; otherwise, if T is a (possibly cv-qualified) unsigned integer type then type denotes the corresponding signed integer type, with the same cv-qualifiers as T; otherwise, type denotes the signed integer type with smallest rank ([conv.rank]) for which sizeof(T) == sizeof(type), with the same cv-qualifiers as T.

Mandates: T is an integral or enumeration type other than cv bool.
template<class T>
struct make_unsigned;
If T is a (possibly cv-qualified) unsigned integer type ([basic.fundamental]) then the member typedef type denotes T; otherwise, if T is a (possibly cv-qualified) signed integer type then type denotes the corresponding unsigned integer type, with the same cv-qualifiers as T; otherwise, type denotes the unsigned integer type with smallest rank ([conv.rank]) for which sizeof(T) == sizeof(type), with the same cv-qualifiers as T.

Mandates: T is an integral or enumeration type other than cv bool.