.\" $NetBSD: strtoi.3,v 1.7.8.1 2024/08/23 18:50:16 martin Exp $ .\" .\" Copyright (c) 1990, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" Chris Torek and the American National Standards Committee X3, .\" on Information Processing Systems. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" from: @(#)strtol.3 8.1 (Berkeley) 6/4/93 .\" .\" Created by Kamil Rytarowski, based on ID: .\" NetBSD: strtol.3,v 1.31 2015/03/11 09:57:35 wiz Exp .\" .Dd January 20, 2024 .Dt STRTOI 3 .Os .Sh NAME .Nm strtoi .Nd convert a string value to an intmax_t integer .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In inttypes.h .Ft intmax_t .Fo strtoi .Fa "const char * restrict nptr" .Fa "char ** restrict endptr" .Fa "int base" .Fa "intmax_t lo" .Fa "intmax_t hi" .Fa "int *rstatus" .Fc .Sh DESCRIPTION The .Fn strtoi function converts the string in .Fa nptr to an .Ft intmax_t value. The .Fn strtoi function uses internally .Xr strtoimax 3 and ensures that the result is always in the range [ .Fa lo .. .Fa hi ]. In adddition it always places .Dv 0 on success or a conversion status in the .Fa rstatus argument, avoiding the .Dv errno gymnastics the other functions require. The .Fa rstatus argument can be .Dv NULL if conversion status is to be ignored. .Pp The string may begin with an arbitrary amount of white space (as determined by .Xr isspace 3 ) followed by a single optional .Ql + or .Ql - sign. If .Fa base is zero or 16, the string may then include a .Ql 0x or .Ql 0X prefix, and the number will be read in base 16; otherwise, .\" if the .\" .Fa base .\" is zero or 2, .\" the string may then include a .\" .Ql 0b .\" or .\" .Ql 0B .\" prefix, .\" and the number will be read in base 2; otherwise, a zero .Fa base is taken as 10 (decimal) unless the next character is .Ql 0 , in which case it is taken as 8 (octal). .Pp The remainder of the string is converted to an .Em intmax_t value in the obvious manner, stopping at the end of the string or at the first character which is not a valid digit in the given base. (In bases above 10, the letter .Ql A in either upper or lower case represents 10, .Ql B represents 11, and so forth, with .Ql Z representing 35.) .Pp If .Fa endptr is non-nil, .Fn strtoi stores the address of the first invalid character in .Fa *endptr . If there were no digits at all, however, .Fn strtoi stores the original value of .Fa nptr in .Fa *endptr . (Thus, if .Fa *nptr is not .Ql \e0 but .Fa **endptr is .Ql \e0 on return, the entire string was valid.) .Sh RETURN VALUES The .Fn strtoi function always returns the closest value in the range specified by the .Fa lo and .Fa hi arguments. .Pp The .Va errno value is guaranteed to be left unchanged. .Pp Errors are stored as the conversion status in the .Fa rstatus argument. .Sh EXAMPLES The following example will always return a number in .Dv [1..99] range no matter what the input is, and warn if the conversion failed. .Bd -literal -offset indent 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); .Ed .Sh ERRORS .Bl -tag -width Er .It Bq Er ECANCELED The string did not contain any characters that were converted. .It Bq Er EINVAL The .Ar base is not between 2 and 36 and does not contain the special value 0. .It Bq Er ENOTSUP The string contained non-numeric characters that did not get converted. In this case, .Fa endptr points to the first unconverted character. .It Bq Er ERANGE The given string was out of range; the value converted has been clamped; or the range given was invalid, i.e. .Fa lo > .Fa hi . .El .Pp The range check is more important than the unconverted characters check, and it is performed first. If a program needs to know if there were unconverted characters when an out of range number has been provided, it needs to supply and test .Fa endptr. .Sh SEE ALSO .Xr atof 3 , .Xr atoi 3 , .Xr atol 3 , .Xr atoll 3 , .Xr strtod 3 , .Xr strtoimax 3 , .Xr strtol 3 , .Xr strtoll 3 , .Xr strtou 3 , .Xr strtoul 3 , .Xr strtoull 3 , .Xr strtoumax 3 .Sh STANDARDS The .Fn strtoi function is a .Nx extension. .Sh HISTORY The .Fn strtoi function first appeared in .Nx 7 . .Ox introduced the .Fn strtonum 3 function for the same purpose, but the interface makes it impossible to properly differentiate illegal returns. .Sh BUGS Ignores the current locale.