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STRTOUL(3) FreeBSD 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>
#include <limits.h>
unsigned long
strtoul(const char * restrict nptr, char ** restrict endptr, int base);
unsigned long long
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 *nptr, char **endptr, int base);
DESCRIPTION
The strtoul() function converts the string in nptr to an unsigned long
value. The strtoull() function converts the string in nptr to an
unsigned long long 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 "0b" prefix, and the
number will be read in base 2; or it may 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 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 nptr in *endptr. (Thus, if *nptr is not
`\0' but **endptr is `\0' on return, the entire string was valid.)
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
portable 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.
SEE ALSO
strtol(3), strtonum(3), wcstoul(3)
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.
FreeBSD 14.0-RELEASE-p11 August 21, 2023 FreeBSD 14.0-RELEASE-p11