NAME

SYNOPSIS

void random_range_seed(int seed)
long random_range(int min, int max, int mult, char **errp)
long random_rangel(long min, long max, long mult, char **errp)
long long random_rangell(long long min, long long max,
		         long long mult, char **errp)
long random_bit(long mask)

DESCRIPTION

random_range() chooses a random number in the range min-max (inclusive) which is a multiple of mult. min and max may be any integer, but mult must be a positive integer greater than 0. errp is a char ** which is used to detect error conditions. If errp is not NULL, *errp will be set to point to an error message. If errp is NULL, error conditions cannot be detected by the caller. If mult is 1 (the most common case), there are no possible error conditions, and the return value is guaranteed to be valid.

random_range_seed() sets the random number generator seed to the specified value.

random_bit() will return a randomly selected single bit bitmask from the bits set in mask. The bit is randomly chosen using random_range(). If mask is zero, zero is returned.

random_range() functions uses lrand48() internally. If the range is bigger than will fit in a 32 bit long (2G), lrand48() with a a internal recursive algorithm to produce a random number.

EXAMPLES

#include <stdio.h>
main(argc, argv)
int	argc;
char	**argv;
{
	int		r;
	char		*errp;
	extern void	random_range_seed();
	extern long	random_range();
	random_range_seed(getpid());
	r = random_range(atoi(argv[1]), atoi(argv[2]), atoi(argv[3]), &errp);
	if (errp == NULL) {
		fprintf(stderr, "random_range failed:  %s0, errp);
		exit(1);
	} else {
		printf("%d0, r);
	}
	exit(0);
}

SEE ALSO

DIAGNOSTICS

BUGS

On IRIX systems, random_range() can only produce a 32 number. random_rangel() when compiled as a 32 bit object is still limited to 32 bit number. random_rangell() can be used to return a value bigger than 32 bits even when compiled as a 32 bit object.