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ASN1_TYPE_get(3)                    OpenSSL                   ASN1_TYPE_get(3)

       ASN1_TYPE_get, ASN1_TYPE_set, ASN1_TYPE_set1, ASN1_TYPE_cmp,
       ASN1_TYPE_unpack_sequence, ASN1_TYPE_pack_sequence - ASN1_TYPE utility

       libcrypto, -lcrypto

        #include <openssl/asn1.h>

        int ASN1_TYPE_get(const ASN1_TYPE *a);
        void ASN1_TYPE_set(ASN1_TYPE *a, int type, void *value);
        int ASN1_TYPE_set1(ASN1_TYPE *a, int type, const void *value);
        int ASN1_TYPE_cmp(const ASN1_TYPE *a, const ASN1_TYPE *b);

        void *ASN1_TYPE_unpack_sequence(const ASN1_ITEM *it, const ASN1_TYPE *t);
        ASN1_TYPE *ASN1_TYPE_pack_sequence(const ASN1_ITEM *it, void *s,
                                           ASN1_TYPE **t);

       These functions allow an ASN1_TYPE structure to be manipulated. The
       ASN1_TYPE structure can contain any ASN.1 type or constructed type such
       as a SEQUENCE: it is effectively equivalent to the ASN.1 ANY type.

       ASN1_TYPE_get() returns the type of a.

       ASN1_TYPE_set() sets the value of a to type and value. This function
       uses the pointer value internally so it must not be freed up after the

       ASN1_TYPE_set1() sets the value of a to type a copy of value.

       ASN1_TYPE_cmp() compares ASN.1 types a and b and returns 0 if they are
       identical and non-zero otherwise.

       ASN1_TYPE_unpack_sequence() attempts to parse the SEQUENCE present in t
       using the ASN.1 structure it. If successful it returns a pointer to the
       ASN.1 structure corresponding to it which must be freed by the caller.
       If it fails it return NULL.

       ASN1_TYPE_pack_sequence() attempts to encode the ASN.1 structure s
       corresponding to it into an ASN1_TYPE. If successful the encoded
       ASN1_TYPE is returned. If t and *t are not NULL the encoded type is
       written to t overwriting any existing data. If t is not NULL but *t is
       NULL the returned ASN1_TYPE is written to *t.

       The type and meaning of the value parameter for ASN1_TYPE_set() and
       ASN1_TYPE_set1() is determined by the type parameter.  If type is
       V_ASN1_NULL value is ignored. If type is V_ASN1_BOOLEAN then the
       boolean is set to TRUE if value is not NULL. If type is V_ASN1_OBJECT
       then value is an ASN1_OBJECT structure. Otherwise type is and
       ASN1_STRING structure. If type corresponds to a primitive type (or a
       string type) then the contents of the ASN1_STRING contain the content
       octets of the type. If type corresponds to a constructed type or a
       tagged type (V_ASN1_SEQUENCE, V_ASN1_SET or V_ASN1_OTHER) then the
       ASN1_STRING contains the entire ASN.1 encoding verbatim (including tag
       and length octets).

       ASN1_TYPE_cmp() may not return zero if two types are equivalent but
       have different encodings. For example the single content octet of the
       boolean TRUE value under BER can have any non-zero encoding but
       ASN1_TYPE_cmp() will only return zero if the values are the same.

       If either or both of the parameters passed to ASN1_TYPE_cmp() is NULL
       the return value is non-zero. Technically if both parameters are NULL
       the two types could be absent OPTIONAL fields and so should match,
       however passing NULL values could also indicate a programming error
       (for example an unparseable type which returns NULL) for types which do
       not match. So applications should handle the case of two absent values

       ASN1_TYPE_get() returns the type of the ASN1_TYPE argument.

       ASN1_TYPE_set() does not return a value.

       ASN1_TYPE_set1() returns 1 for success and 0 for failure.

       ASN1_TYPE_cmp() returns 0 if the types are identical and non-zero

       ASN1_TYPE_unpack_sequence() returns a pointer to an ASN.1 structure or
       NULL on failure.

       ASN1_TYPE_pack_sequence() return an ASN1_TYPE structure if it succeeds
       or NULL on failure.

       Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at

1.1.1                             2018-09-17                  ASN1_TYPE_get(3)