Bad conversion from int to unsigned char

[tanis2000]

I'm using hxcpp version 3.3.49 and Lime 3.0.0

I transpile the SimpleImage example of Lime to iOS (but any native C++ target is the same).

When compiling I get the following error:

./src/lime/graphics/format/BMP.cpp:307:23: warning: implicit conversion from 'int' to 'unsigned char' changes value from 11824 to 48 [-Wconstant-conversion]


            data->b[position] = (int)11824;

Since some of those values are also negative or bigger than a char, they become 0 during the assignment, thus leading to bugs.
Example:

./src/lime/graphics/format/BMP.cpp:402:35: warning: implicit conversion from 'int' to 'unsigned char' changes value from -65536 to 0 [-Wconstant-conversion]


                    data->b[(position + (int)1)] = (int)-65536;

Here's the generated BMP.cpp file: https://gist.github.com/tanis2000/d2e9e1d700c13aef0d6c035e2b9811f9#file-bmp-cpp-L307
And here's the original BMP.hx file: https://gist.github.com/tanis2000/3181b0c23184da839d4eda80ba125ca6

[hughsando]

I don't think this should generate bugs, since setting the value to 0 is
actually the desired behaviour.
To be completely correct, It should be something like:

data->b[(position + (int)1)] = ( (int)-65536 ) & 0xff;

But this number is just 0 anyhow.

I should do something about the warnings though - in case there is a
real warning that needs checking.

On Wed, Jul 13, 2016 at 4:06 PM, Valerio Santinelli <
notifications@github.com> wrote:

I'm using hxcpp version 3.3.49 and Lime 3.0.0

I transpile the SimpleImage example of Lime to iOS (but any native C++
target is the same).

When compiling I get the following error:

./src/lime/graphics/format/BMP.cpp:307:23: warning: implicit conversion from 'int' to 'unsigned char' changes value from 11824 to 48 [-Wconstant-conversion]

        data->b[position] = (int)11824;

Since some of those values are also negative or bigger than a char, they
become 0 during the assignment, thus leading to bugs.
Example:

./src/lime/graphics/format/BMP.cpp:402:35: warning: implicit conversion from 'int' to 'unsigned char' changes value from -65536 to 0 [-Wconstant-conversion]

                data->b[(position + (int)1)] = (int)-65536;

Here's the generated BMP.cpp file:
https://gist.github.com/tanis2000/d2e9e1d700c13aef0d6c035e2b9811f9#file-bmp-cpp-L307
And here's the original BMP.hx file:
https://gist.github.com/tanis2000/3181b0c23184da839d4eda80ba125ca6

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