Klaus Heinz wrote:
> Hi,
> 
> "pkglint -e -Wall" says
> 
> 
>   WARN: Makefile:17: Permission [a] requested for USE_LANGUAGES, but only
>   [s] is allowed.
> 
>         The available permissions are:
>                 a       append something using +=
>                 d       set a default value using ?=
>                 s       set a variable using :=, =, !=
>                 p       use a variable during preprocessing
>                 u       use a variable at runtime
> 
>         A "?" means that it is not yet clear which permissions are allowed
>         and which aren't.
> 
> Is this warning for USE_LANGUAGES+= correct?

Yes, it is.

> The action for target "fail-wrapper:" in mk/compiler.mk explicitly tells
> us
> 
>   *** Please consider adding USE_LANGUAGES+=...

The one who wrote that wasn't me, so that may be the reason for the 
inconsistency. I've fixed the wording of that warning.

> In chapter 23.2, the pkgsrc guide tells us more about USE_LANGUAGES but
> I do not understand what it says.

Hmm, that was me who wrote it. I still know what I wanted to say, but 
it's so badly expressed that I can't expect anyone to understand it. :(

> Are we supposed to explicitly list a C compiler as necessary or can we
> rely on the pkgsrc guide (and the comment in compiler.mk) that
> 
>   The default is "c"

The default value is "c", but since it is not documented _when_ that 
default value is set, you should not use the "+=" operator with that 
variable.

Example 1 (doesn't work as expected):

     # $NetBSD$
     ...
     USE_LANGUAGES+=  c++
     ...
     .include "../../mk/bsd.pkg.mk"

In this case, USE_LANGUAGES will only have c++, but not c. The reason is 
that when the default value is supposed to be set, the variable already 
has a value, so nothing happens.

Example 2 (also doesn't work as expected):

     # $NetBSD$
     ...
     .include "../../mk/compiler.mk"
     USE_LANGUAGES+=  c++
     ...
     .include "../../mk/bsd.pkg.mk"

In this case, USE_LANGUAGES has the value "c c++", but the 
c++-fail-wrapper is created nevertheless. This is because compiler.mk is 
protected from multiple inclusion, so the USE_LANGUAGES variable is 
never inspected after the first .include line.

Example 3 (works perfectly):

     # $NetBSD$
     ...
     USE_LANGUAGES=    c c++
     ...
     .include "../../mk/bsd.pkg.mk"

When you want something else than the default value, you have to 
overwrite the complete value using the = operator.

Roland