strtoi(3bsd)

1STRTOI(3bsd)                         LOCAL                        STRTOI(3bsd)
2

NAME

4     strtoi — convert string value to an intmax_t integer
5

LIBRARY

7     Utility functions from BSD systems (libbsd, -lbsd)
8

SYNOPSIS

10     #include <inttypes.h>
11     (See libbsd(7) for include usage.)
12
13     intmax_t
14     strtoi(const char * restrict nptr, char ** restrict endptr, int base,
15         intmax_t lo, intmax_t hi, int *rstatus);
16

DESCRIPTION

18     The strtoi() function converts the string in nptr to an intmax_t value.
19     The strtoi() function uses internally strtoimax(3) and ensures that the
20     result is always in the range [ lo .. hi ].  In adddition it always
21     places 0 on success or a conversion status in the rstatus argument,
22     avoiding the errno gymnastics the other functions require.  The rstatus
23     argument can be NULL if conversion status is to be ignored.
24
25     The string may begin with an arbitrary amount of white space (as deter‐
26     mined by isspace(3)) followed by a single optional ‘+’ or ‘-’ sign.  If
27     base is zero or 16, the string may then include a ‘0x’ or ‘0X’ prefix,
28     and the number will be read in base 16; otherwise, a zero base is taken
29     as 10 (decimal) unless the next character is ‘0’, in which case it is
30     taken as 8 (octal).
31
32     The remainder of the string is converted to a intmax_t value in the obvi‐
33     ous manner, stopping at the first character which is not a valid digit in
34     the given base.  (In bases above 10, the letter ‘A’ in either upper or
35     lower case represents 10, ‘B’ represents 11, and so forth, with ‘Z’ rep‐
36     resenting 35.)
37
38     If endptr is non-nil, strtoi() stores the address of the first invalid
39     character in *endptr.  If there were no digits at all, however, strtoi()
40     stores the original value of nptr in *endptr.  (Thus, if *nptr is not
41     ‘\0’ but **endptr is ‘\0’ on return, the entire string was valid.)
42

RETURN VALUES

44     The strtoi() function always returns the closest value in the range spec‐
45     ified by the lo and hi arguments.
46
47     The errno value is guaranteed to be left unchanged.
48
49     Errors are stored as the conversion status in the rstatus argument.
50

EXAMPLES

52     The following example will always return a number in [1..99] range no
53     matter what the input is, and warn if the conversion failed.
54
55           int e;
56           intmax_t lval = strtoi(buf, NULL, 0, 1, 99, &e);
57           if (e)
58                   warnc(e, "conversion of `%s' to a number failed, using %jd",
59                       buf, lval);
60

ERRORS

62     [ECANCELED]        The string did not contain any characters that were
63                        converted.
64
65     [EINVAL]           The base is not between 2 and 36 and does not contain
66                        the special value 0.
67
68     [ENOTSUP]          The string contained non-numeric characters that did
69                        not get converted.  In this case, endptr points to the
70                        first unconverted character.
71
72     [ERANGE]           The given string was out of range; the value converted
73                        has been clamped; or the range given was invalid, i.e.
74                        lo > hi.
75

STANDARDS

81     The strtoi() function is a NetBSD extension.
82

HISTORY

84     The strtoi() function first appeared in NetBSD 7.  OpenBSD introduced the
85     strtonum(3bsd) function for the same purpose, but the interface makes it
86     impossible to properly differentiate illegal returns.
87

BUGS

89     Ignores the current locale.
90
91BSD                            November 13, 2015                           BSD