BN_set_bit.3ssl - Man Page

bit operations on BIGNUMs

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);

Description

BN_set_bit() sets bit n in a to 1 (a|=(1<<n)). The number is expanded if necessary.

BN_clear_bit() sets bit n in a to 0 (a&=~(1<<n)). 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 (a&=~((~0)>>n)).  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 (r=a*2^n). Note that n must be non-negative. BN_lshift1() shifts a left by one and places the result in r (r=2*a).

BN_rshift() shifts a right by n bits and places the result in r (r=a/2^n). Note that n must be non-negative. BN_rshift1() shifts a right by one and places the result in r (r=a/2).

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

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 ERR_get_error(3).

See Also

BN_num_bytes(3), BN_add(3)

Referenced By

bn.3ssl(3), BN_add.3ssl(3).

The man pages BN_clear_bit.3ssl(3), BN_is_bit_set.3ssl(3), BN_lshift1.3ssl(3), BN_lshift.3ssl(3), BN_mask_bits.3ssl(3), BN_rshift1.3ssl(3) and BN_rshift.3ssl(3) are aliases of BN_set_bit.3ssl(3).

2020-06-03 1.1.1g OpenSSL