# strtouq

## Name

strtouq -- convert a string to an unsigned long long

## Synopsis

#include <sys/types.h>
#include <stdlib.h>
#include <limits.h> |

```
unsigned long long
````strtouq`

(const char *
*nptr*, char * *
*endptr*, int
*base*);

## Description

`strtouq()` converts the string *nptr*
to an unsigned long long
value. The conversion is done according to the given base, which
shall be between `2` and `36` inclusive,
or be the special value `0`.

*nptr* may begin with an arbitrary amount of white
space (as determined by `isspace()`), followed by a
single optional + or - sign character. If
*base* is `0` or `16`,
the string may then include a 0x prefix, and the number will
be read in base 16; otherwise, a `0` base is taken as
10 (decimal), unless the next character is `0`, in which
case it is taken as 8 (octal).

The remainder of the string is converted to an unsigned long value in the
obvious manner, stopping at the end of the string or at the first character
that does not produce a valid digit in the given base. (In bases above 10,
the letter `A` in either upper or lower case represents 10,
`B` represents 11, and so forth, with `Z`
representing 35.)

## Return Value

On success, `strtouq()` returns either the result of
the conversion or, if there was a leading minus sign, the negation of
the result of the conversion, unless the original (non-negated) value
would overflow. In the case of an overflow the function returns
`UQUAD_MAX`

and the global variable `errno`

is set to ERANGE.

## Errors

ERANGE | | The given string was out of range; the value converted has been clamped. |