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Title "BN_SET_BIT 3"
BN_SET_BIT 3 "2023-02-07" "1.1.1t" "OpenSSL"
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"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
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #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); .Ve
"DESCRIPTION"
Header "DESCRIPTION" \fBBN_set_bit() sets bit n in a to 1 (\*(C`a|=(1<<n)\*(C'). The number is expanded if necessary.

\fBBN_clear_bit() sets bit n in a to 0 (\*(C`a&=~(1<<n)\*(C'). An error occurs if a is shorter than n bits.

\fBBN_is_bit_set() tests if bit n in a is set.

\fBBN_mask_bits() truncates a to an n bit number (\*(C`a&=~((~0)<<n)\*(C'). An error occurs if a already is shorter than n bits.

\fBBN_lshift() shifts a left by n bits and places the result in \fBr (\*(C`r=a*2^n\*(C'). Note that n must be nonnegative. BN_lshift1() shifts \fBa left by one and places the result in r (\*(C`r=2*a\*(C').

\fBBN_rshift() shifts a right by n bits and places the result in \fBr (\*(C`r=a/2^n\*(C'). Note that n must be nonnegative. BN_rshift1() shifts \fBa right by one and places the result in r (\*(C`r=a/2\*(C').

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

"RETURN VALUES"
Header "RETURN VALUES" \fBBN_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 ERR_get_error\|(3).

"SEE ALSO"
Header "SEE ALSO" \fBBN_num_bytes\|(3), BN_add\|(3)
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.