Subtract unsigned BIGNUMs: r = a - b (requires a >= b).
r
a
b
b).
Declared in <openssl/bn.h>
<openssl/bn.h>
int BN_usub( BIGNUM* r, BIGNUM const* a, BIGNUM const* b);
1 on success, or 0 if a < b or on error.
a.