The manual already describes how posix_spawn(3) behaves when passing it a NULL envp, but does not make it clear that it is an OpenBSD extension:
> If envp is NULL, the environment is passed unchanged from the parent > process. That differs from GNU/Linux, for example, where a NULL envp gives the child an empty environment rather than a copy. Index: posix_spawn.3 =================================================================== RCS file: /cvs/src/lib/libc/gen/posix_spawn.3,v retrieving revision 1.9 diff -u -p -r1.9 posix_spawn.3 --- posix_spawn.3 17 Oct 2017 22:47:58 -0000 1.9 +++ posix_spawn.3 25 Jun 2023 21:38:47 -0000 @@ -122,6 +122,10 @@ with exit status 127. .Sh STANDARDS Both functions conform to .St -p1003.1-2001 . +.Pp +The handling of NULL +.Fa envp +is an extension to that standard. .Sh HISTORY These functions were ported from .Fx
