Re: POSIXLY_CORRECT not correctly unset in getopt.m4?

[Bruno Haible]

Eric Blake wrote:
> env is required by POSIX, but it is not (yet) listed in the list of 
> programs safe to use in GNU Coding Standards

And 'env' would not help much, because its output can easily be confused
by environment variable values that contain newlines:

  $ foo='not
  POSIXLY_CORRECT=1'
  $ export foo
  $ env | grep POSIXLY_CORRECT
  POSIXLY_CORRECT=1
  $ echo ${POSIXLY_CORRECT+set}

> Any other ideas for portable ways of detecting whether a shell variable 
> is currently local-only or exported?

'printenv' does not exist on Solaris.

But 'awk' is among the list of portable programs. This should work:

  if test `awk 'BEGIN { print ENVIRON["POSIXLY_CORRECT"] }' < /dev/null | wc 
-c` = 1; then
    : # POSIXLY_CORRECT is not exported
  else
    : # POSIXLY_CORRECT is exported
  fi

Maybe the test whether the value of ENVIRON["POSIXLY_CORRECT"] is empty or
non-empty can be moved into the awk script. I'm not very familiar with awk
programming.

Bruno