Re: Global xtrace from function

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Jul 20,  5:20pm, Thorsten Kampe wrote:
}
} is it possible to `setopt xtrace` from within a function without 
} having xtrace unset when exiting the function? That seems to be the 
} default behaviour for Bash's `shopt -os xtrace`.

The options XTRACE, PRINT_EXIT_VALUE, LOCAL_OPTIONS, and LOCAL_LOOPS
are always reset on exit from a function.  (I'm not sure why the
LOCAL_TRAPS and LOCAL_PATTERNS options aren't in that list as well,
except "because they're newer and nobody thought of it.")  Zsh has
behaved this way since before the source was under version control.

It's possible that we ought to skip resetting xtrace when in posix
shell emulation mode.

You can get the effect you want with

    this_sets_xtrace() { trap 'setopt xtrace' EXIT }

except of course in posix emulation (POSIX_TRAPS), when exit traps
aren't executed for shell functions ...