Re: numeric_limits<float>::max

[Jim Blandy]

This sounds like a real bug.  However, we really can't work on
something without a way to reproduce the behavior ourselves.  So if
you do come up with a small test program, at the very least we'll
included it in our test suite, to remind us that the bug is there.

Gabriel Zachmann <address@hidden> writes:

> I have a funny problem with gdb (GNU gdb Red Hat Linux (5.1-1)):
> 
> In a C++ program I have the following two lines:
> 
>     float v = -numeric_limits<float>::max();
>     fprintf(stderr,"v=%f\n", v );
> 
> When I run the program I always get the output
> 
>     v=-340282346638528859811704183484516925440.000000
> 
> However, when I run the program in gdb I sometimes get this
> 
>     375     float v = -numeric_limits<float>::max();
>     (gdb) 
>     376     fprintf(stderr,"v=%f\n", v );
>     (gdb) 
>     v=nan
> 
>       ^^^
> 
> Unfortunately, I seem to be unable to produce a small example program
> exhibiting this behavior.
> 
> I compile the program with g++ 3.0.4 using these options:
> 
>     -march=i686 -ansi -fno-default-inline -ffor-scope
>     -g3 -ggdb3 -Wall -W -Wpointer-arith
>     -Wcast-qual -Wcast-align -Wconversion -Woverloaded-virtual -Wsign-compare
>     -Wnon-virtual-dtor -Woverloaded-virtual -Wfloat-equal -Wmissing-prototypes
>     -Wunreachable-code -Wno-reorder -D_GNU_SOURCE 
> 
> Does anybody have any idea what might cause this differing behavior?
> 
> Thanks a lot in advance,
> Gabriel.
> 
> 
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