I found the gettext.h provided by the package and I included it in my program .
I had to modify the file gettext.h, to add #define ENABLE_NLS 1 before the if.
In my mlinux c program, I included those two files :
then I've done that :
printf(" local: %s\n", acTest);
acTest= bindtextdomain("Alwin", LANGUAGE_DIR);
printf(" bind domain : %s\n", acTest);
printf(" textdomain: %s\n", acTest);
which it works, the return value correspond of what I've entered !
Just after, I set my language with :
setenv ("LANGUAGE", acLanguage, 1);
then I try a hello world with :
acTest = gettext("hello");