1=pod 2 3=head1 NAME 4 5BN_CTX_new, BN_CTX_init, BN_CTX_free - allocate and free BN_CTX structures 6 7=head1 SYNOPSIS 8 9 #include <openssl/bn.h> 10 11 BN_CTX *BN_CTX_new(void); 12 13 void BN_CTX_init(BN_CTX *c); 14 15 void BN_CTX_free(BN_CTX *c); 16 17=head1 DESCRIPTION 18 19A B<BN_CTX> is a structure that holds B<BIGNUM> temporary variables used by 20library functions. Since dynamic memory allocation to create B<BIGNUM>s 21is rather expensive when used in conjunction with repeated subroutine 22calls, the B<BN_CTX> structure is used. 23 24BN_CTX_new() allocates and initializes a B<BN_CTX> 25structure. BN_CTX_init() initializes an existing uninitialized 26B<BN_CTX>. 27 28BN_CTX_free() frees the components of the B<BN_CTX>, and if it was 29created by BN_CTX_new(), also the structure itself. 30If L<BN_CTX_start(3)|BN_CTX_start(3)> has been used on the B<BN_CTX>, 31L<BN_CTX_end(3)|BN_CTX_end(3)> must be called before the B<BN_CTX> 32may be freed by BN_CTX_free(). 33 34 35=head1 RETURN VALUES 36 37BN_CTX_new() returns a pointer to the B<BN_CTX>. If the allocation fails, 38it returns B<NULL> and sets an error code that can be obtained by 39L<ERR_get_error(3)|ERR_get_error(3)>. 40 41BN_CTX_init() and BN_CTX_free() have no return values. 42 43=head1 SEE ALSO 44 45L<bn(3)|bn(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<BN_add(3)|BN_add(3)>, 46L<BN_CTX_start(3)|BN_CTX_start(3)> 47 48=head1 HISTORY 49 50BN_CTX_new() and BN_CTX_free() are available in all versions on SSLeay 51and OpenSSL. BN_CTX_init() was added in SSLeay 0.9.1b. 52 53=cut 54