Can not find any function definition in GTK library files.

[Aditi Barua <aditi ankur org bd>]

hello all,
 I m trying to solve a rendering problem in the GTK library.
i used a bangla Language text in a button level and when i give a Bangla full stop it changes the the position of charecters of the text.
This situation occurs in windows operating system. for linux it is Bangla text rendering is working fine.

I used a function gtk_button_new_with_label to set the button level.
as this function is responsible for asigning the button level and thus
rendering also occured some how in this function i wanted to find out
the definition of this function. 
 but the library that i have seen in my installation folder only contain function prototype. 
there is no function definition for any of the function that my program is used.
i have downloaded the GTK_ bundle from 
http://www.gtk.org/download-windows.html and unzip it in MINGW installation folder.

i have downloaded the individual GTK+ source file from the same site
it has the function descrisption in C files

I replaced the GTK source file (gtk+-2.16.1\gtk) where i found the
library definition in the GTK bundle (C:\MinGW\include) but it is not
referencing the file containing gtk_button_new_with_label function
definition.

Normally in C the definition of printf can be found in stdio.h file.
but GTK libraries does using the file containing their function definition. 
how is it compiling its library function.

Can anyone give me any idea.
 
Aditi