strtoul, strtoull, strtoumax, strtouq - convert a string to an unsigned
long, unsigned long long, uintmax_t or uquad_t integer
Standard C Library (libc, -lc)
#include <stdlib.h>
#include <limits.h>
unsigned long int
strtoul(const char * restrict nptr, char ** restrict endptr, int base);
unsigned long long int
strtoull(const char * restrict nptr, char ** restrict endptr, int base);
#include <inttypes.h>
uintmax_t
strtoumax(const char * restrict nptr, char ** restrict endptr, int base);
#include <sys/types.h>
#include <stdlib.h>
#include <limits.h>
u_quad_t
strtouq(const char * restrict nptr, char ** restrict endptr, int base);
The strtoul() function converts the string in nptr to an unsigned long
int value. The strtoull() function converts the string in nptr to an
unsigned long long int value. The strtoumax() function converts the
string in nptr to an uintmax_t value. The strtouq() function converts
the string in nptr 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 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 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.)
If endptr is non nil, 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 nptr in *endptr. (Thus, if *nptr is not
`\0' but **endptr is `\0' on return, the entire string was valid.)
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, strtoull() returns ULLONG_MAX,
strtoumax() returns UINTMAX_MAX, and the global variable errno is set to
ERANGE.
[ERANGE] The given string was out of range; the value converted
has been clamped.
strtoimax(3), strtol(3), strtoll(3)
The strtoul() function conforms to ANSI X3.159-1989 (``ANSI C''). The
strtoull() and strtoumax() functions conform to .
Ignores the current locale.
BSD April 26, 2001 BSD
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