2847. sin(float) should call sinf(float)

Section: 29.9.1 [cmath.syn] Status: New Submitter: Jens Maurer Opened: 2016-12-15 Last modified: 2017-02-02

Priority: 3

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Discussion:

With P0175R1, we now show in [cmath.syn] three overloads for the sin function: One taking a float, one taking a double, and one taking a long double. However, there is no statement that sin(long double) should actually invoke sinl, presumably delivering extra precision.

An implementation like

inline long double sin(long double x)
{ return sinf(x); }

seems to satisfy the "effectively cast" requirement, but is certainly unintentional.

The same issue arises for all math functions inherited from C.

(Source: Editorial issue #1247)

[2017-01-27 Telecon]

Priority 3

Proposed resolution: