strtoi(3bsd) LOCAL strtoi(3bsd)
NAME
strtoi — convert string value to an intmax_t integer
LIBRARY
Utility functions from BSD systems (libbsd, -lbsd)
SYNOPSIS
#include <inttypes.h>
(See libbsd(7) for include usage.)
intmax_t
strtoi(const char * restrict nptr, char ** restrict endptr, int base,
intmax_t lo, intmax_t hi, int *rstatus);
DESCRIPTION
The strtoi() function converts the string in nptr to an intmax_t value.
The strtoi() function uses internally strtoimax(3) and ensures that the
result is always in the range [ lo .. hi ]. In adddition it always
places 0 on success or a conversion status in the rstatus argument,
avoiding the errno gymnastics the other functions require. The rstatus
argument can be NULL if conversion status is to be ignored.
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’ or ‘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 a intmax_t value in the obvi-
ous 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’ rep-
resenting 35.)
If endptr is non-nil, strtoi() stores the address of the first invalid
character in *endptr. If there were no digits at all, however, strtoi()
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.)
RETURN VALUES
The strtoi() function always returns the closest value in the range spec-
ified by the lo and hi arguments.
The errno value is guaranteed to be left unchanged.
Errors are stored as the conversion status in the rstatus argument.
EXAMPLES
The following example will always return a number in [1..99] range no
matter what the input is, and warn if the conversion failed.
int e;
intmax_t lval = strtoi(buf, NULL, 0, 1, 99, &e);
if (e)
warnc(e, "conversion of `%s' to a number failed, using %jd",
buf, lval);
ERRORS
[ECANCELED] The string did not contain any characters that were
converted.
[EINVAL] The base is not between 2 and 36 and does not contain
the special value 0.
[ENOTSUP] The string contained non-numeric characters that did
not get converted. In this case, endptr points to the
first unconverted character.
[ERANGE] The given string was out of range; the value converted
has been clamped; or the range given was invalid, i.e.
lo > hi.
SEE ALSO
atof(3), atoi(3), atol(3), atoll(3), strtod(3), strtoimax(3), strtol(3),
strtoll(3), strtou(3bsd), strtoul(3), strtoull(3), strtoumax(3)
STANDARDS
The strtoi() function is a NetBSD extension.
HISTORY
The strtoi() function first appeared in NetBSD 7.0. OpenBSD introduced
the strtonum(3bsd) function for the same purpose, but the interface makes
it impossible to properly differentiate illegal returns.
BUGS
Ignores the current locale.
BSD November 13, 2015 BSD
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