Re: using if statement

[Philip Guenther]

On 5/4/07, Eli Zaretskii <address@hidden> wrote:
> From: "Satish Somasundaram" <address@hidden>
...
> >            for dir in `$(SUB_DIRS)`; do \
> >            $(MAKE) -C $$dir; \
> >            done
>
> Does the following (100% untested) modification work?
>
>             for dir in `$(SUB_DIRS)`; do \
>             $(MAKE) -C $$dir || (echo "ERROR" && exit 1); \
>             done

So close...  By wrapping the echo and exit in parens, you force them
to be performed by a subshell, so the exit doesn't affect the parent
shell which make is watching.  You need to either use braces instead
of parens or leave out the echo.

i.e., leaving out the echo:
            for dir in `$(SUB_DIRS)`; do \
                $(MAKE) -C $$dir || exit $$?; \
            done

(note: $$? will be expanded by make to $?, which the shell will then
expand to the exit status of the previous command)


vs using braces:
            for dir in `$(SUB_DIRS)`; do \
                $(MAKE) -C $$dir || { echo "ERROR" && exit 1; } \
            done

(Yes, the semicolon before the close brace is required, as braces are
"reserved words" and not "meta-characters" for the shell...)

Personally, I prefer the "no echo and no braces" version, as make is
noisy enough about the non-zero exit as is.


Philip Guenther