.Dd $Mdocdate: February 23 2015 $
.Dt BN_CMP 3
.Os
.Sh NAME
.Nm BN_cmp ,
.Nm BN_ucmp ,
.Nm BN_is_zero ,
.Nm BN_is_one ,
.Nm BN_is_word ,
.Nm BN_is_odd
.Nd BIGNUM comparison and test functions
.Sh SYNOPSIS
.In openssl/bn.h
.Ft int
.Fo BN_cmp
.Fa "BIGNUM *a"
.Fa "BIGNUM *b"
.Fc
.Ft int
.Fo BN_ucmp
.Fa "BIGNUM *a"
.Fa "BIGNUM *b"
.Fc
.Ft int
.Fo BN_is_zero
.Fa "BIGNUM *a"
.Fc
.Ft int
.Fo BN_is_one
.Fa "BIGNUM *a"
.Fc
.Ft int
.Fo BN_is_word
.Fa "BIGNUM *a"
.Fa "BN_ULONG w"
.Fc
.Ft int
.Fo BN_is_odd
.Fa "BIGNUM *a"
.Fc
.Sh DESCRIPTION
.Fn BN_cmp
compares the numbers
.Fa a
and
.Fa b .
.Fn BN_ucmp
compares their absolute values.
.Pp
.Fn BN_is_zero ,
.Fn BN_is_one
and
.Fn BN_is_word
test if
.Fa a
equals 0, 1, or
.Fa w
respectively.
.Fn BN_is_odd
tests if a is odd.
.Pp
.Fn BN_is_zero ,
.Fn BN_is_one ,
.Fn BN_is_word ,
and
.Fn BN_is_odd
are macros.
.Sh RETURN VALUES
.Fn BN_cmp
returns -1 if
.Fa a Ns < Ns Fa b ,
0 if
.Fa a Ns == Ns Fa b ,
and 1 if
.Fa a Ns > Ns Fa b .
.Fn BN_ucmp
is the same using the absolute values of
.Fa a
and
.Fa b .
.Pp
.Fn BN_is_zero ,
.Fn BN_is_one ,
.Fn BN_is_word ,
and
.Fn BN_is_odd
return 1 if the condition is true, 0 otherwise.
.Sh SEE ALSO
.Xr bn 3
.Sh HISTORY
.Fn BN_cmp ,
.Fn BN_ucmp ,
.Fn BN_is_zero ,
.Fn BN_is_one
and
.Fn BN_is_word
are available in all versions of SSLeay and OpenSSL.
.Fn BN_is_odd
was added in SSLeay 0.8.