STRTOUL(3) Linux Programmer's Manual STRTOUL(3)
**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 spe-
cial 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 dig-
its 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 orig-
inal (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 con-
verted 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.
GNU March 29, 1993 1