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Re: isinf
Joe Buck <Joe.Buck@synopsys.COM> writes:
>> >> The configure script which is included in rrdtool[1] checks whether
>> >> the system has isinf() as below.
>> >>
>> >> #include <math.h>
>> >> int
>> >> main ()
>> >> {
>> >> float f = 0.0; isinf(f)
>> >> ;
>> >> return 0;
>> >> }
>> >
>> > The test is clearly fragile. Assigning the return value of isinf to a
>> > variable should be sufficient for 4.0.x at -O0.
>
> Best to make it a global variable, to guard against dead code elimination.
Oops, the configure script compiling with -O2 optimization. The
compilation of the following code still suceesss.
#include <math.h>
int a;
int
main ()
{
float f = 0.0;
a = isinf (f);
return 0;
}
Do I misunderstand? Since I am the newbie of C, I consulted this page:
http://www.phim.unibe.ch/comp_doc/c_manual/C/SYNTAX/glo_int_vars.html
--
Hiroshi Fujishima