void f(char c, signed char sc, unsigned char uc)
{
    char∗ pc = &uc; // error : no pointer conversion
    signed char∗ psc = pc; // error : no pointer conversion
    unsigned char∗ puc = pc; // error : no pointer conversion
    psc = puc; // error : no pointer conversion
}
void g(char c, signed char sc, unsigned char uc)
{
    c = 255; // implementation-defined if plain chars are signed and have 8 bits
    c = sc; // OK
    c = uc; // implementation-defined if plain chars are signed and if uc’s value is too large
    sc = uc; // implementation defined if uc’s value is too large
    uc = sc; // OK: conversion to unsigned
    sc = c; // implementation-defined if plain chars are unsigned and if c’s value is too large
    uc = c; // OK: conversion to unsigned
}