conio.h

The header file contains prototypes for functions that affect the console and I/O ports within the computer in a very direct way. These are non portable between different types of computers and should be avoided unless speed or functionality makes them necessary. Unfortunately, on PCs these functions get used a lot. On more sophisticated operating systems they can usually be avoided. These functions are:

    cgets()      cscanf()    inp()     outp()    ungetch()
    cprintf()    getch()     inpw()    outpw()
    cputs()      getche()    kbhit()   putch()

These functions tend to differ between different compilers for the same machine too.