#include <err.h>


#ifndef HAVE_STRTONUM
#include <stdlib.h>
#include <limits.h>
#include <errno.h>

#define INVALID         1
#define TOOSMALL        2
#define TOOLARGE        3

long long
strtonum(const char *numstr, long long minval, long long maxval,
    const char **errstrp)
{
        long long ll = 0;
        char *ep;
        int error = 0;
        struct errval {
                const char *errstr;
                int err;
        } ev[4] = {
                { NULL,         0 },
                { "invalid",    EINVAL },
                { "too small",  ERANGE },
                { "too large",  ERANGE },
        };

        ev[0].err = errno;
        errno = 0;
        if (minval > maxval)
                error = INVALID;
        else {
                ll = strtoll(numstr, &ep, 10);
                if (numstr == ep || *ep != '\0')
                        error = INVALID;
                else if ((ll == LLONG_MIN && errno == ERANGE) || ll < minval)
                        error = TOOSMALL;
                else if ((ll == LLONG_MAX && errno == ERANGE) || ll > maxval)
                        error = TOOLARGE;
        }
        if (errstrp != NULL)
                *errstrp = ev[error].errstr;
        errno = ev[error].err;
        if (error)
                ll = 0;

        return (ll);
}

#endif /* HAVE_STRTONUM */


int
main(void) {
        char            *substring="100";     
	const char      *errstr;
		
	strtonum(substring, 50, 200, errstr);
        (errstr)
        warnx("number of buttons is %s: %s", errstr, substring);
        return 0;

}