Standard C++ Library Reference ISO/IEC (VERSION3)

In locales other than the "C" locale, strtol can define additional patterns as well.
If the string s does not match a valid pattern, the value stored in *endptr is s, and x is zero.
If the equivalent value is too large to represent as type long, strtol stores the value of
ERANGE in errno and returns either LONG_MAX, if x is positive, or LONG_MIN, if x is
negative.
strtoul
unsigned long strtoul(const char *s, char **endptr,
int base);
The function converts the initial characters of the string s to an equivalent value x of type
unsigned long. If endptr is not a null pointer, it stores a pointer to the unconverted remainder
of the string in *endptr. The function then returns x.
strtoul converts strings exactly as does strtol, but reports a range error only if the
equivalent value is too large to represent as type unsigned long. In this case, strtoul stores
the value of ERANGE in errno and returns ULONG_MAX.
system
int system(const char *s);
If s is not a null pointer, the function passes the string s to be executed by a command
processor, supplied by the target environment, and returns the status reported by the command
processor. If s is a null pointer, the function returns nonzero only if the target environment
supplies a command processor. Each implementation defines what strings its command
processor accepts.
wchar_t
typedef i-type wchar_t; [keyword in C++]
The type is the integer type i-type of a wide-character constant, such as L'X'. You declare
an object of type wchar_t to hold a wide character.
wcstombs
size_t wcstombs(char *s, const wchar_t *wcs, size_t n);
The function stores a multibyte string, in successive elements of the array whose first element
has the address s, by converting in turn each of the wide characters in the string wcs. The