Defined in header <cinttypes>  

std::intmax_t wcstoimax( const wchar_t* nptr, wchar_t** endptr, int base );  (since C++11)  
std::uintmax_t wcstoumax( const wchar_t* nptr, wchar_t** endptr, int base );  (since C++11) 
Interprets an unsigned integer value in a wide string pointed to by nptr
.
Discards any whitespace characters (as identified by calling isspace()
) until the first nonwhitespace character is found, then takes as many characters as possible to form a valid basen (where n=base) unsigned integer number representation and converts them to an integer value. The valid unsigned integer value consists of the following parts:
0
) indicating octal base (applies only when the base is 8
or 0
) 0x
or 0X
) indicating hexadecimal base (applies only when the base is 16
or 0
) The set of valid values for base is {0,2,3,...,36}. The set of valid digits for base2 integers is {0,1
}, for base3 integers is {0,1,2
}, and so on. For bases larger than 10
, valid digits include alphabetic characters, starting from Aa
for base11 integer, to Zz
for base36 integer. The case of the characters is ignored.
Additional numeric formats may be accepted by the currently installed C locale
.
If the value of base is 0
, the numeric base is autodetected: if the prefix is 0
, the base is octal, if the prefix is 0x
or 0X
, the base is hexadecimal, otherwise the base is decimal.
If the minus sign was part of the input sequence, the numeric value calculated from the sequence of digits is negated as if by unary minus in the result type, which applies unsigned integer wraparound rules.
The functions sets the pointer pointed to by endptr
to point to the wide character past the last character interpreted. If endptr
is NULL
, it is ignored.
nptr    pointer to the nullterminated wide string to be interpreted 
endptr    pointer to a pointer to a wide character. 
base    base of the interpreted integer value 
Integer value corresponding to the contents of str
on success. If the converted value falls out of range of corresponding return type, range error occurs and INTMAX_MAX
, INTMAX_MIN
, UINTMAX_MAX
, or 0
is returned, as appropriate. If no conversion can be performed, 0
is returned.
#include <iostream> #include <string> #include <cinttypes> int main() { std::wstring str = L"helloworld"; std::intmax_t val = std::wcstoimax(str.c_str(), nullptr, 36); std::wcout << str << " in base 36 is " << val << " in base 10\n"; wchar_t* nptr; val = std::wcstoimax(str.c_str(), &nptr, 30); if(nptr != &str[0] + str.size()) std::wcout << str << " in base 30 is invalid." << " The first invalid digit is " << *nptr << '\n'; }
Output:
helloworld in base 36 is 1767707668033969 in base 10 helloworld in base 30 is invalid. The first invalid digit is w
(C++11)(C++11)  converts a byte string to std::intmax_t or std::uintmax_t (function) 
converts a wide string to an integer value (function) 

converts a wide string to an unsigned integer value (function) 

C documentation for wcstoimax, wcstoumax 
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