Re: macro which returns found compiler for given language?

[Diab Jerius]

On Mon, May 11, 2015 at 1:14 PM, Diab Jerius <address@hidden> wrote:
> On Mon, May 11, 2015 at 12:40 PM, Daily, Jeff A <address@hidden> wrote:
>>> -----Original Message-----
>>> From: address@hidden [mailto:autoconf-
>>> address@hidden On Behalf Of Diab Jerius
>>> Sent: Monday, May 11, 2015 8:59 AM
>>> To: address@hidden
>>> Subject: macro which returns found compiler for given language?
>>>
>>> I'm trying to determine the version of GNU Fortran by parsing the
>>> compiler's standard output when passed the --version option.
>>>
>>> I cannot use AC_COMPILE_IFELSE, as the compiler doesn't generate an
>>> object file when passed --version, and AC_COMPILE_IFELSE requires that
>>> for success.
>>>
>>> I've resorted to using the _AC_CC macro to get the name of the
>>> compiler so that I can execute it directly, but that's not good
>>> practice.
>>>
>>> Is there a public macro which provides the compiler for a given language?
>>
>> Why do you need an autoconf macro to provide this?
>>
>> If a shell variable is sufficient, then use the following:
>>
>> C -> $CC
>> C++ -> $CXX
>> Fortran77 -> $F77
>> Fortran -> $FC
>>
>> These output variables are documented in the autoconf manual under 
>> AC_PROG_CC, AC_PROG_CXX, AC_PROG_F77, AC_PROG_FC, respectively.
>
>
> D'oh! You know, I think I knew that once upon a time.

Unfortunately, after further thought, the output variables aren't
sufficient for what I need.

As the code cannot assume which flavor of Fortran is being tested,
without more information it cannot choose between F77 or FC.

If the current language were known, the code could choose
appropriately, but the only macro available (AFAIK)  to query the
current language is AC_LANG_ASSERT, which is inappropriate in this
context.  It'd be much cleaner if one could get the compiler for the
current language, or have _AC_CC exposed as part of the public API.