Floating point traps are triggered by alien code.

[ender]

When making foreign function calls (with sb-alien or a wrapper such as cffi), sbcl will trap floating point errors that happen in the C code, and by default sbcl traps on errors that aren't typically on in c code (the default mode in C99 is to be in nonstop mode, ie no fp exceptions trigger a SIGFPE).

This means that foreign function calls need to be wrapped in sb-int:with-float-traps-masked or clear traps with sb-ing:set-floating-point-modes. Both of which are awkward and tricky to use portably.

SBCL should probably make foreign function calls with the floating point environment set to the default.

[Gábor Melis (melisgl)]

ender <email address hidden> writes:

> This means that foreign function calls need to be wrapped in sb-int
> :with-float-traps-masked or clear traps with sb-ing:set-floating-point-
> modes. Both of which are awkward and tricky to use portably.
>
> SBCL should probably make foreign function calls with the floating point
> environment set to the default.

+1 from user's point of view.

[Vinced (vincezd)]

It affects us on the IUP library: https://github.com/lispnik/iup/issues/30 We are forced to run our snippets with

```
#+sbcl
(sb-int:with-float-traps-masked
    (:divide-by-zero :invalid)
  (callback))
```

[Michał "phoe" Herda (phoe-krk)]

Also visible in cl-opengl - https://github.com/3b/cl-opengl/issues/98

[Stas Boukarev (stassats)]

What is visible in cl-opengl? That "SBCL should probably make foreign function calls with the floating point environment set to the default." will make everything slow?