BN_add_word(3)

BN_add_word(3) | OpenSSL | BN_add_word(3)

# NAME

BN_add_word, BN_sub_word, BN_mul_word, BN_div_word, BN_mod_word - arithmetic functions on BIGNUMs with integers

# SYNOPSIS

     #include <openssl/bn.h>
     int BN_add_word(BIGNUM *a, BN_ULONG w);
     int BN_sub_word(BIGNUM *a, BN_ULONG w);
     int BN_mul_word(BIGNUM *a, BN_ULONG w);
     BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w);
     BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);

# DESCRIPTION

These functions perform arithmetic operations on BIGNUMs with unsigned integers. They are much more efficient than the normal BIGNUM arithmetic operations.

BN_add_word() adds w to a ("a+=w").

BN_sub_word() subtracts w from a ("a-=w").

BN_mul_word() multiplies a and w ("a*=w").

BN_div_word() divides a by w ("a/=w") and returns the remainder.

BN_mod_word() returns the remainder of a divided by w ("a%w").

For BN_div_word() and BN_mod_word(), w must not be 0.

# RETURN VALUES

BN_add_word(), BN_sub_word() and BN_mul_word() return 1 for success, 0 on error. The error codes can be obtained by ERR_get_error(3).

BN_mod_word() and BN_div_word() return a%w on success and (BN_ULONG)-1 if an error occurred.

# SEE ALSO

ERR_get_error(3), BN_add(3)

# 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 <https://www.openssl.org/source/license.html>.

2025-07-01 | 3.5.1