Quote:Original post by ApochPiQ Neither of your tests will cause an obvious problem with coercing them to floats from doubles. Try something like 1e50 which is out of float's range, and you'll get a warning (unless you're being stupid and not runnning with a high warning level).
Quote: dmail@x1-6-00-11-2f-24-88-81:~/gcc_warning> gcc -ansi -pedantic -pedantic-errors -Wall -Wextra float_double.c float_double.c: In function ‘main’: float_double.c:5: warning: unused variable ‘f2’ float_double.c:4: warning: unused variable ‘f1’ float_double.c:3: warning: unused variable ‘f’ dmail@x1-6-00-11-2f-24-88-81:~/gcc_warning> cat float_double.c int main() { float f = 1.0/3.0; float f1 = 56355465468487.3; float f2 = 1e50; return 0; } dmail@x1-6-00-11-2f-24-88-81:~/gcc_warning>
Why would I be being stupid? you can see the error and warning flags I am passing to the compiler.
Same code, but with icc in place of gcc :
Quote: arkhyl@zeus:~$ icc -ansi -Wall -o test float_double.c float_double.c(3): remark #810: conversion from "double" to "float" may lose significant bits float f = 1.0/3.0; ^ float_double.c(5): warning #264: floating-point value does not fit in required floating-point type float f2 = 1e50; ^ float_double.c(3): remark #177: variable "f" was declared but never referenced float f = 1.0/3.0; ^ float_double.c(4): remark #177: variable "f1" was declared but never referenced float f1 = 56355465468487.3; ^ float_double.c(5): remark #177: variable "f2" was declared but never referenced float f2 = 1e50;
Quote: dmail@x1-6-00-11-2f-24-88-81:~/gcc_warning> gcc -ansi -pedantic -pedantic-errors -Wall -Wextra float_double.c float_double.c: In function ‘main’: float_double.c:5: warning: unused variable ‘f2’ float_double.c:4: warning: unused variable ‘f1’ float_double.c:3: warning: unused variable ‘f’ dmail@x1-6-00-11-2f-24-88-81:~/gcc_warning> cat float_double.c int main() { float f = 1.0/3.0; float f1 = 56355465468487.3; float f2 = 1e50; return 0; } dmail@x1-6-00-11-2f-24-88-81:~/gcc_warning>
Why would I be being stupid? you can see the error and warning flags I am passing to the compiler.
I also get the same behaviour with gcc-4.2.3 using C++, which I was little surprised about. I tried to poke it but without any luck...
philpalk@innerchild:~$ g++ -ansi -pedantic -pedantic-errors -Wall -Wextra main.cppphilpalk@innerchild:~$ cat main.cppdouble dostuff(float f){ return f;}int main(){ float f = 1e50; double d = 1e50; f = d; f = dostuff(1e50);}philpalk@innerchild:~$
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