Hi again ;-) I do have the following C struct: typedef unsigned long tcflag_t; typedef unsigned char cc_t; typedef long speed_t; /* XXX should be unsigned long */ struct termios { tcflag_t c_iflag; /* input flags */ tcflag_t c_oflag; /* output flags */ tcflag_t c_cflag; /* control flags */ tcflag_t c_lflag; /* local flags */ cc_t c_cc[NCCS]; /* control chars */ speed_t c_ispeed; /* input speed */ speed_t c_ospeed; /* output speed */ }; with NCCS being #define'd to 20. I need to allocate space for this struct and therefore want to know its size ... As I don't need the struct itself I thought about calculating the size but I figure there's the problem of getting all the padding to count to the size... How would I do that ? Thx!! Frank