NAME¶

std::stoul,std::stoull - std::stoul,std::stoull

Synopsis¶

Defined in header <string>
unsigned long stoul ( const std::string& str,
std::size_t* pos = nullptr, int base = (1) (since C++11)
10 );
unsigned long stoul ( const std::wstring& str,
std::size_t* pos = nullptr, int base = (2) (since C++11)
10 );
unsigned long long stoull( const std::string& str,
std::size_t* pos = nullptr, int base = (3) (since C++11)
10 );
unsigned long long stoull( const std::wstring& str,
std::size_t* pos = nullptr, int base = (4) (since C++11)
10 );

Interprets an unsigned integer value in the string str.

Let ptr be an internal (to the conversion functions) pointer of type char* (1,3) or
wchar_t* (2,4), accordingly.

1) Calls std::strtoul(str.c_str(), &ptr, base).
2) Calls std::wcstoul(str.c_str(), &ptr, base).
3) Calls std::strtoull(str.c_str(), &ptr, base).
4) Calls std::wcstoull(str.c_str(), &ptr, base).

Discards any whitespace characters (as identified by calling std::isspace) until the
first non-whitespace character is found, then takes as many characters as possible
to form a valid base-n (where n=base) unsigned integer number representation and
converts them to an integer value. The valid unsigned integer value consists of the
following parts:

* (optional) plus or minus sign
* (optional) prefix (0) indicating octal base (applies only when the base is 8 or
0)
* (optional) prefix (0x or 0X) indicating hexadecimal base (applies only when the
base is 16 or 0)
* a sequence of digits

The set of valid values for base is {0,2,3,...,36}. The set of valid digits for
base-2 integers is {0,1}, for base-3 integers is {0,1,2}, and so on. For bases
larger than 10, valid digits include alphabetic characters, starting from Aa for
base-11 integer, to Zz for base-36 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 auto-detected: 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.

If pos is not a null pointer, then ptr will receive the address of the first
unconverted character in str.c_str(), and the index of that character will be
calculated and stored in *pos, giving the number of characters that were processed
by the conversion.

Parameters¶

str - the string to convert
pos - address of an integer to store the number of characters processed
base - the number base

Return value¶

The string converted to the specified unsigned integer type.

Exceptions¶

* std::invalid_argument if no conversion could be performed.
* std::out_of_range if the converted value would fall out of the range of the
result type or if the underlying function (std::strtoul or std::strtoull) sets
errno to ERANGE.

Example¶

This section is incomplete
Reason: no example

Defect reports

The following behavior-changing defect reports were applied retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
std::out_of_range would not be thrown if
LWG 2009 C++11 std::strtoul or std::strtoull sets errno to will throw
ERANGE

See also¶

stoi
stol
stoll converts a string to a signed integer
(C++11) (function)
(C++11)
(C++11)
stof
stod
stold converts a string to a floating point value
(C++11) (function)
(C++11)
(C++11)

Category:¶

* Todo no example