Re: [Tinycc-devel] sinf/sin problems

[Lee Duhem]

On Wed, Dec 24, 2014 at 10:08 AM, Oleg N. Cher <address@hidden> wrote:
> Hi all,
>
> float version sinf does not work as expected:
>
> #include <stdio.h>
> #include <math.h>
>
> int main(int argc, char **argv) {
>  float f = sinf(0.1);
>  printf("%f", f);
>  return 0;
> }
>
>>tcc testsinf.c
> tcc: error: undefined symbol 'sinf'

`sinf' is defined in libm.so, you need to link with it. So try this:

tcc testsinf.c -lm


> Next question is a very evil problem, I think. if #include <Math> not
> specified, absolutely no bugs/warnings,

-Wall will give you the warning that you expected.

> but code works wrong:

The code is, sort of, right, your expectation of what it should do is
wrong.

As explained by Aharon, c compiler will offer an implicit declaration
for any undeclared function that it saw, and the return type of this
implicit declaration is `int'. Therefore those return values of `sin' in
your code will be converted to `int' first, then convert to `double' for
`printf' to print. That why it only prints "0.000000".

Add `#include <math.h>' should fix this problem.

Sincerely,
lee

>
>
> #include <stdio.h>
>
> int main(int argc, char **argv) {
>
>  printf("\n%f", sin(-3.0));
>  printf("\n%f", sin(-2.0));
>  printf("\n%f", sin(-1.0));
>  printf("\n%f", sin(0.0));
>  printf("\n%f", sin(1.0));
>  printf("\n%f", sin(2.0));
>  printf("\n%f", sin(3.0));
>  printf("\n%f", sin(3.1415926));
>
>  return 0;
> }
>
>>tcc testsinf.c
>>testsinf.exe
>
> 0.000000
> 0.000000
> 0.000000
> 0.000000
> 0.000000
> 0.000000
> 0.000000
> 0.000000
>
> Please agree with me that this must be fixed.
>
> Thank you.
>
>
> --
> Oleg
>
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