wrapper

aamutakki

kääre

löysä vaatekappale Something that is wrapped around something else as a cover or protection: a wrapping.
An outer garment; a loose robe or dressing gown.
1839, (w), ‘William Wilson’:

‘Please to examine, at your leisure, the inner linings of the cuff of his left sleeve, and the several little packages which may be found in the somewhat capacious pockets of his embroidered morning wrapper.’

He proved to be a remarkably efficient wrapper of parcels.

We need a Perl wrapper for this C++ library.