Date: Sun, 25 Mar 2018 22:22:18 -0700 (PDT) From: Don Lewis <truckman@FreeBSD.org> To: freebsd@dreamchaser.org Cc: FreeBSD Mailing List <freebsd-ports@freebsd.org> Subject: Re: .if and Makefile issues Message-ID: <tkrat.f98dfb3939b1bfe1@FreeBSD.org> In-Reply-To: <85769c6d-a71a-f2c6-8a65-ac9b82f534ab@dreamchaser.org> References: <85769c6d-a71a-f2c6-8a65-ac9b82f534ab@dreamchaser.org>
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On 25 Mar, Gary Aitken wrote:
> Bewildered and frustrated, looking for some guidance on a seemingly
> simple task: check the existence of a file and rename it.
>
> Looking at a number of examples in the Porter's guide, I should be
> able to do something like this:
>
> post-build:
> <ht>echo "***** post-build *****"
> #<ht>Avoid executable name conflict with dcraw port
> <ht>.if exists ${WRKSRC}/dcraw
> <ht>echo ===== dcraw exists =====
> <ht>mv ${WRKSRC}/dcraw ${WRKSRC}/${PORTNAME}-dcraw
> <ht>.else
> <ht>echo ===== dcraw does not exist =====
> <ht>.endif
>
> That causes:
> echo "***** post-build *****"
> ***** post-build *****
> .if exists /usr/ports/graphics/ufraw-devel/work/ufraw-6d3259a/dcraw
> make[1]: exec(.if) failed (No such file or directory)
> *** Error code 1
Since the .if is indented, it is being treated as a shell command,
and .if isn't being found in $PATH.
> I then tried adding parens:
>
> post-build:
> <ht>echo "***** post-build *****"
> #<ht>Avoid executable name conflict with dcraw port
> <ht>.if exists(${WRKSRC}/dcraw)
> <ht>echo "===== dcraw exists ====="
> <ht>mv ${WRKSRC}/dcraw ${WRKSRC}/${PORTNAME}-dcraw
> <ht>.else
> <ht>echo "===== dcraw does not exist ====="
> <ht>.endif
>
> echo "***** post-build *****"
> ***** post-build *****
> .if exists(/usr/ports/graphics/ufraw-devel/work/ufraw-6d3259a/dcraw)
> Syntax error: "(" unexpected
> *** Error code 2
Ditto, but the shell command has a shell syntax error.
> I finally got this to do *something*:
>
> post-build:
> <ht>echo "***** post-build *****"
> # Avoid executable name conflict with dcraw port
> .if exists ${WRKSRC}/dcraw
> echo ===== dcraw exists =====
> mv ${WRKSRC}/dcraw ${WRKSRC}/${PORTNAME}-dcraw
> .else
> <ht>echo ===== dcraw does not exist =====
> .endif
>
> echo "***** post-build *****"
> ***** post-build *****
> echo "===== dcraw does not exist ====="
> ===== dcraw does not exist =====
>
> Unfortunately, the file *does* exist.
The .if is treated as a make directive in this case, but it is
evaluated at the time that make is first invoked, probably when
when "make build" is first executed, or earlier.
> Can someone enlighten me as to what is going on in the above three
> situations, to further my education?
> Any hints / pointers would be much appreciated:
>
> 1. Why does the .if, .else, and .endif have to have no leading whitespace?
If there is leading whitespace, then make assumes they are shell
commands.
> 2. Why does it require the <ht> on the stmt after the else but not
> after the .if? (Same behavior with tabs on the ones after .if)
Probably because the .if evaluates false, so anything between the .if
and the .else isn't even parsed.
> 3. Why doesn't it find the file?
Because the file doesn't exist when the make first parses the Makefile.
> 4. What's a right way to do this?
Use a shell runtime test:
post-build:
<ht>echo "***** post-build *****"
<ht># Avoid executable name conflict with dcraw port
<ht>if [ -e ${WRKSRC}/dcraw ]; then
<ht><ht>echo ===== dcraw exists =====
<ht><ht>mv ${WRKSRC}/dcraw ${WRKSRC}/${PORTNAME}-dcraw
<ht>else
<ht><ht>echo ===== dcraw does not exist =====
<ht>fi
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