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manpages-nl_20051127-4_all **NAME**

strtoul - convert a string to an unsigned long integer.

**SYNOPSIS**

**#include** **<stdlib.h>**
**unsigned** **long** **int** **strtoul(const** **char** *****__nptr__**,** **char** ******__endptr__**,**
**int** base**)**

**DESCRIPTION**

The **strtoul()** function converts the string in __nptr__ to an unsigned long
integer value according to the given __base__, which must be between 2 and
36 inclusive, or be the special value 0.
The string must begin with an arbitrary amount of white space (as
determined by **isspace**(3)) followed by a single optional ‘+’ or ‘-’
sign. If __base__ is zero or 16, the string may then include a ‘0x’
prefix, and the number will be read in base 16; otherwise, a zero __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 int value
in the obvious manner, stopping at the first character which is not 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.)
If __endptr__ is not NULL, **strtoul()** stores the address of the first
invalid character in __*endptr__. If there were no digits at all,
**strtoul()** stores the original value of __nptr__ in __*endptr__. (Thus, if
__*nptr__ is not ‘\0’ but __**endptr__ is ‘\0’ on return, the entire string is
valid.)

**RETURN** **VALUE**

The **strtoul()** function 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 latter case, **strtoul()** returns ULONG_MAX and sets the global
variable __errno__ to ERANGE.

**ERRORS**

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

**CONFORMING** **TO**

SVID 3, BSD 4.3, ISO 9899

**SEE** **ALSO**

**atof**(3), **atoi**(3), **atol**(3), **strtod**(3), **strtol**(3)

**BUGS**

Ignores the current locale.