Re: isinf and type-pun warning/error on OSF guile 1.8.7

[Andy Wingo <wingo@pobox.com>]

Hi Jay,

On Wed 09 Jun 2010 17:43, Jay K <jay.krell@cornell.edu> writes:

> libtool: compile:  gcc -DHAVE_CONFIG_H -I.. -I/home/jayk/src/guile-1.8.7 -I.. -mieee -mieee -D_REENTRANT -pthread -g -O2 -Wall -Wmissing-prototypes -Werror -MT libguile_la-numbers.lo -MD -MP -MF .deps/libguile_la-numbers.Tpo -c /home/jayk/src/guile-1.8.7/libguile/numbers.c  -DPIC -o .libs/libguile_la-numbers.o
> cc1: warnings being treated as errors
> /home/jayk/src/guile-1.8.7/libguile/numbers.c: In function 'xisinf':
> /home/jayk/src/guile-1.8.7/libguile/numbers.c:144: error: implicit
> declaration of function 'isinf'

> I couldn't find isinf in any header. 

This call only occurs if configure detected support `isinf', so surely
it is there? Can you check again? Barring that can you send a
config.log, please.

> /home/jayk/src/guile-1.8.7/libguile/numbers.c: In function 'guile_ieee_init':
> /home/jayk/src/guile-1.8.7/libguile/numbers.c:623: error: dereferencing type-punned pointer will break strict-aliasing rules
> /home/jayk/src/guile-1.8.7/libguile/numbers.c:654: error: dereferencing type-punned pointer will break strict-aliasing rules

Does replacing that DINIFINITY block with the following help?

  /* OSF */
  extern unsigned int DINFINITY[2];
  union
  {
    double d;
    int i[2];
  } alias;
  alias.i[0] = DINFINITY[0];
  alias.i[1] = DINFINITY[1];
  guile_Inf = alias.d;

Likewise for DQNAN:

  {
    /* OSF */
    extern unsigned int DQNAN[2];
    union
    {
      double d;
      int i[2];
    } alias;
    alias.i[0] = DQNAN[0];
    alias.i[1] = DQNAN[1];
    guile_NaN = alias.d;
  }

> I recall seeing the same problem on Irix, where autoconf does a link check
> and compiles without -Wmissing-prototype so it passes, because the function
> does exist somewhere. Autoconf checks need to more closely resemble
> how later compilation will occur.

How does that work though -- does isinf have no header/declaration?

> /home/jayk/src/guile-1.8.7/test-suite/standalone/test-conversion.c:859:
> error: dereferencing type-punned pointer will break strict-aliasing
> rules make[4]: *** [test_conversion-test-conversion.o] Error 1

We can copy the above solution if it works. Let us know!

Andy
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