Invalid foreign-procedure convention __collect_safe

[Mariano Montone]

I get this when I try to use __collect_safe foreign-procedure convention:

Exception: invalid foreign-procedure convention __collect_safe

Even if I try to run the example from: https://cisco.github.io/ChezScheme/csug9.5/foreign.html

(define c-sleep (foreign-procedure __collect_safe "sleep" (unsigned) unsigned)) (c-sleep 10) ; sleeps for 10 seconds without blocking other threads

$ chezscheme collect-safe.sls Chez Scheme Version 9.5 Copyright 1984-2017 Cisco Systems, Inc. 

Exception: invalid foreign-procedure convention __collect_safe at line 2, char 22 of collect-safe.sls

I'm on Linux and Chez version 9.5

[Mariano Montone]

__collect_safe was introduced in version 9.5.1. I was using too old version of Chez.