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table of contents

std::stoul,std::stoull(3) | C++ Standard Libary | std::stoul,std::stoull(3) |

# 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

2024.06.10 | http://cppreference.com |