- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- SEE ALSO
- HISTORY

# 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.

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

# SEE ALSO

bn, ERR_get_error, BN_add

# HISTORY

`BN_add_word()` and `BN_mod_word()` are available in all versions of SSLeay and OpenSSL. `BN_div_word()` was added in SSLeay 0.8, and `BN_sub_word()` and `BN_mul_word()` in SSLeay 0.9.0.

Before 0.9.8a the return value for `BN_div_word()` and `BN_mod_word()` in case of an error was 0.