BN_CTX_new(3) — Subroutines

NAME

BN_CTX_new, BN_CTX_init, BN_CTX_free − Allocate and free BN_CTX structures

SYNOPSIS

#include <openssl/bn.h>
BN_CTX ∗BN_CTX_new(
        void ); void BN_CTX_init(
        BN_CTX ∗c ); void BN_CTX_free(
        BN_CTX ∗c );

DESCRIPTION

A BN_CTX is a structure that holds BIGNUM temporary variables used by library functions. Since dynamic memory allocation to create BIGNUMs is rather expensive when used in conjunction with repeated subroutine calls, the BN_CTX structure is used.

The BN_CTX_new() function allocates and initializes a BN_CTX structure. The BN_CTX_init() function initializes an existing uninitialized BN_CTX.

The BN_CTX_free() function frees the components of the BN_CTX, and if it was created by BN_CTX_new(), also the structure itself. If BN_CTX_start() has been used on the BN_CTX, BN_CTX_end() must be called before the BN_CTX may be freed by BN_CTX_free().

RETURN VALUES

BN_CTX_new() returns a pointer to the BN_CTX. If the allocation fails, it returns NULL and sets an error code that can be obtained by ERR_get_error().

The BN_CTX_init() and BN_CTX_free() functions have no return values.

HISTORY

The BN_CTX_new() and BN_CTX_free() functions are available in all versions on SSLeay and OpenSSL. The BN_CTX_init() function was added in SSLeay 0.9.1b.

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