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<ul id="index">
 <li><a href="#NAME">NAME</a></li>
 <li><a href="#SYNOPSIS">SYNOPSIS</a></li>
 <li><a href="#DESCRIPTION">DESCRIPTION</a></li>
 <li><a href="#RETURN-VALUES">RETURN VALUES</a></li>
 <li><a href="#SEE-ALSO">SEE ALSO</a></li>
 <li><a href="#COPYRIGHT">COPYRIGHT</a></li>
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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

<h1 id="SYNOPSIS">SYNOPSIS</h1>

<pre><code> #include &lt;openssl/bn.h&gt;

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);</code></pre>

<h1 id="DESCRIPTION">DESCRIPTION</h1>

BN_set_bit() sets bit n in a to 1 (<code>a|=(1&lt;&lt;n)</code>). The number is expanded if necessary.

BN_clear_bit() sets bit n in a to 0 (<code>a&amp;=~(1&lt;&lt;n)</code>). An error occurs if a is shorter than n bits.

BN_is_bit_set() tests if bit n in a is set.

BN_mask_bits() truncates a to an n bit number (<code>a&amp;=~((~0)&lt;&lt;n)</code>). An error occurs if a already is shorter than n bits.

BN_lshift() shifts a left by n bits and places the result in r (<code>r=a*2^n</code>). Note that n must be nonnegative. BN_lshift1() shifts a left by one and places the result in r (<code>r=2*a</code>).

BN_rshift() shifts a right by n bits and places the result in r (<code>r=a/2^n</code>). Note that n must be nonnegative. BN_rshift1() shifts a right by one and places the result in r (<code>r=a/2</code>).

For the shift functions, r and a may be the same variable.

<h1 id="RETURN-VALUES">RETURN VALUES</h1>

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 <a href="../man3/ERR_get_error.html">ERR_get_error(3)</a>.

<a href="../man3/BN_num_bytes.html">BN_num_bytes(3)</a>, <a href="../man3/BN_add.html">BN_add(3)</a>

<h1 id="COPYRIGHT">COPYRIGHT</h1>

Licensed under the OpenSSL license (the &quot;License&quot;). 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 <a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.

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