Joe Buck <[EMAIL PROTECTED]> 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