openssl/doc/man3/BN_set_bit.pod
Gustaf Neumann 490c87110c Align documentation with recommendations of Linux Documentation Project
This change applies the recommendation of the Linux Documentation Project
to the documentation files of OpenSSL. Additionally, util/find-doc-nits
was updated accordingly.

The change follows a suggestion of mspncp on https://github.com/openssl/openssl/pull/12370
and incoporates the requested changes on the pull request

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/12460)
2020-07-22 09:15:00 +02:00

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=pod
=head1 NAME
BN_set_bit, BN_clear_bit, BN_is_bit_set, BN_mask_bits, BN_lshift,
BN_lshift1, BN_rshift, BN_rshift1 - bit operations on BIGNUMs
=head1 SYNOPSIS
#include <openssl/bn.h>
int BN_set_bit(BIGNUM *a, int n);
int BN_clear_bit(BIGNUM *a, int n);
int BN_is_bit_set(const BIGNUM *a, int n);
int BN_mask_bits(BIGNUM *a, int n);
int BN_lshift(BIGNUM *r, const BIGNUM *a, int n);
int BN_lshift1(BIGNUM *r, BIGNUM *a);
int BN_rshift(BIGNUM *r, BIGNUM *a, int n);
int BN_rshift1(BIGNUM *r, BIGNUM *a);
=head1 DESCRIPTION
BN_set_bit() sets bit B<n> in B<a> to 1 (C<a|=(1E<lt>E<lt>n)>). The
number is expanded if necessary.
BN_clear_bit() sets bit B<n> in B<a> to 0 (C<a&=~(1E<lt>E<lt>n)>). An
error occurs if B<a> is shorter than B<n> bits.
BN_is_bit_set() tests if bit B<n> in B<a> is set.
BN_mask_bits() truncates B<a> to an B<n> bit number
(C<a&=~((~0)E<gt>E<gt>n)>). An error occurs if B<a> already is
shorter than B<n> bits.
BN_lshift() shifts B<a> left by B<n> bits and places the result in
B<r> (C<r=a*2^n>). Note that B<n> must be nonnegative. BN_lshift1() shifts
B<a> left by one and places the result in B<r> (C<r=2*a>).
BN_rshift() shifts B<a> right by B<n> bits and places the result in
B<r> (C<r=a/2^n>). Note that B<n> must be nonnegative. BN_rshift1() shifts
B<a> right by one and places the result in B<r> (C<r=a/2>).
For the shift functions, B<r> and B<a> may be the same variable.
=head1 RETURN VALUES
BN_is_bit_set() returns 1 if the bit is set, 0 otherwise.
All other functions return 1 for success, 0 on error. The error codes
can be obtained by L<ERR_get_error(3)>.
=head1 SEE ALSO
L<BN_num_bytes(3)>, L<BN_add(3)>
=head1 COPYRIGHT
Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
=cut