Compute r = (a - b) mod m.
Declared in <openssl/bn.h>
int
BN_mod_sub(
BIGNUM* r,
BIGNUM const* a,
BIGNUM const* b,
BIGNUM const* m,
BN_CTX* ctx);
1 on success, or 0 on error.
| Name | Description |
|---|---|
| r | Destination BIGNUM. |
| a | Minuend. |
| b | Subtrahend. |
| m | Modulus (must be positive). |
| ctx | Optional BN_CTX for temporaries, or NULL. |