This page is a snapshot from the LWG issues list, see the Library Active Issues List for more information and the meaning of New status.

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

Section: 26.8.1 [cmath.syn] Status: New Submitter: Jens Maurer Opened: 2016-12-15 Last modified: 2020-09-06

Priority: 3

View other active issues in [cmath.syn].

View all other issues in [cmath.syn].

View all issues with New status.

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: