cppdraft_translate/cppdraft/linalg/helpers/real.md

[linalg.helpers.real]

29 Numerics library [numerics]

29.9 Basic linear algebra algorithms [linalg]

29.9.7 Exposition-only helpers [linalg.helpers]

29.9.7.3 real-if-needed [linalg.helpers.real]

1

#

The name real-if-needed denotes an exposition-only function object.

The expression real-if-needed(E) for a subexpression E whose type is T is expression-equivalent to:

• (1.1)

real(E), if T is not an arithmetic type and the expression real(E) is valid, with overload resolution performed in a context that includes the declarationtemplate U real(const U&) = delete; If the function selected by overload resolution does not return the real part of its input, the program is ill-formed, no diagnostic required;

• (1.2)

otherwise, E.