bi_subtract

@brief Perform a subtraction operation between two bigints.

bigint *bi_subtract(
　　BI_CTX * ctx
　　bigint * bia
　　bigint * bib
　　int * is_negative
)

ctx

bia

bib

is_negative

@brief Perform a subtraction operation between two bigints.
@param ctx [in]  The bigint session context.
@param bia [in]  A bigint.
@param bib [in]  Another bigint.
@param is_negative [out] If defined, indicates that the result was negative.
is_negative may be null.
@return The result of the subtraction. The result is always positive.