NAME
    prevprime - nearest prime less than specified number

SYNOPSIS
    prevprime(n [,err])

TYPES
    n		real
    err		integer

    return	positive integer or err

DESCRIPTION
    If n is an integer and 2 < n < 2^32, prevprime(n) returns the
    nearest prime less than n.

    If n <= 2 or >= 2^32 or n is fractional, prevprime(n, err)
    returns the value of err.

    Other cases cause a runtime error.

EXAMPLE
    > print prevprime(10), prevprime(100), prevprime(1e6)
    7 97 999983

    > print prevprime(2,-99), prevprime(2^32,-99)
    -99 -99

    > print prevprime(2)
    pprime arg 1 is <= 2

LIMITS
    none

LIBRARY
    FULL zpprime(ZVALUE z)

SEE ALSO
    nextprime