strtoul(3) BSD Library Functions Manual strtoul(3)
NAME
strtoul, strtoull, strtoumax, strtouq -- convert a string to an unsigned
long, unsigned long long, uintmax_t, or u_quad_t integer
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
unsigned long
strtoul(const char *restrict str, char **restrict endptr, int base);
unsigned long long
strtoull(const char *restrict str, char **restrict endptr, int base);
#include <inttypes.h>
uintmax_t
strtoumax(const char *restrict str, char **restrict endptr, int base);
#include <sys/types.h>
#include <stdlib.h>
#include <limits.h>
u_quad_t
strtouq(const char *str, char **endptr, int base);
DESCRIPTION
The strtoul() function converts the string in str to an unsigned long
value. The strtoull() function converts the string in str to an unsigned
long long value. The strtoumax() function converts the string in str to
an uintmax_t value. The strtouq() function converts the string in str to
a u_quad_t value. The conversion is done according to the given base,
which must be between 2 and 36 inclusive, or be the special value 0.
The string may begin with an arbitrary amount of white space (as deter-
mined 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 value in the
obvious manner, stopping at the end of the string or at the first charac-
ter 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.)
If endptr is not NULL, strtoul() stores the address of the first invalid
character in *endptr. If there were no digits at all, however, strtoul()
stores the original value of str in *endptr. (Thus, if *str is not `\0'
but **endptr is `\0' on return, the entire string was valid.)
RETURN VALUES
The strtoul(), strtoull(), strtoumax() and strtouq() functions return
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, strtoull() returns ULLONG_MAX, strtoumax() returns
UINTMAX_MAX, and strtouq() returns ULLONG_MAX. In all cases, errno is
set to ERANGE. If no conversion could be performed, 0 is returned and
the global variable errno is set to EINVAL (the last feature is not por-
table across all platforms).
ERRORS
[EINVAL] The value of base is not supported or no conversion
could be performed (the last feature is not portable
across all platforms).
[ERANGE] The given string was out of range; the value converted
has been clamped.
LEGACY SYNOPSIS
#include <stdlib.h>
#include <limits.h>
<limits.h> is necessary for the strtoul() and strtoull() functions.
SEE ALSO
strtol(3), strtol_l(3), strtonum(3), wcstoul(3), compat(5)
STANDARDS
The strtoul() function conforms to ISO/IEC 9899:1990 (``ISO C90''). The
strtoull() and strtoumax() functions conform to ISO/IEC 9899:1999
(``ISO C99''). The BSD strtouq() function is deprecated.
BSD November 28, 2001 BSD
Mac OS X 10.8 - Generated Fri Aug 31 15:32:39 CDT 2012