gcc warning about return value truncation

gcc warning about return value truncation

[Yubin Ruan]

Is there any gcc flag to warn about this?

#include <iostream>
#include <cstdint>

int16_t func() {
    int32_t num = INT32_MAX;
    std::cout << "func() called " << num << std::endl;
    return num;
}

int main()
{
    int32_t val = func();
    std::cout << "return value is " << val << std::endl;
}

The return value of func() was truncated because the return type is
accidentally written as int16_t

Thanks,
Yubin

Re: gcc warning about return value truncation

[Liu Hao]

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在 2019/12/29 13:11, Yubin Ruan 写道:
> Is there any gcc flag to warn about this?
> 
> 
> The return value of func() was truncated because the return type is
> accidentally written as int16_t
> 


It's `-Wconversion`. By the way I suggest you add `-Wsign-conversion` in
C++ as well.


-- 
Best regards,
LH_Mouse


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Re: gcc warning about return value truncation

[Yubin Ruan]

Thanks a lot.

On Sun, Dec 29, 2019 at 2:29 PM Liu Hao <lh_mouse@126.com> wrote:
>
> 在 2019/12/29 13:11, Yubin Ruan 写道:
> > Is there any gcc flag to warn about this?
> >
> >
> > The return value of func() was truncated because the return type is
> > accidentally written as int16_t
> >
>
>
> It's `-Wconversion`. By the way I suggest you add `-Wsign-conversion` in
> C++ as well.
>
>
> --
> Best regards,
> LH_Mouse
>