How can I use stbi writing functions?

[GetterSetter]

Hello, if I try to include stbi headers, I receive an error from the linker about multiple definition of stbi_write_.... If I try to use

extern int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
//and so on
 

I receive the following error: undefined reference to stbi_... and it doesn't matter which link order I use. So, how can I use these functions? I need to do it because I have the set of pixels itself, so I think that creating a sf::Texture, updating it with this set, then copying it to an sf::Image and finally calling saveToFile() is a bit inefficient and stupid.
RMK: I'm using static sfml libraries

[kojack]

In one (and only one) of your cpp files that includes the stbi headers, you need to do some defines before the includes:

#define STB_IMAGE_IMPLEMENTATION
#define STB_IMAGE_WRITE_IMPLEMENTATION
 

The first one is needed for the reading functions. The second one for the writing functions.

[GetterSetter]

Yeah, I tried it before starting the topic, and I got the error about multiple definitions of these functions because, I assume, they are already implemented in libsfml-graphics.a.
Oh, I think, I've got your idea. Do you mean that in my cpp file I should only include headers without using defines?