D2I_ASN1_OBJECT(3)

NAME
d2i_ASN1_OBJECT, i2d_ASN1_OBJECT - decode and encode ASN.1 object identifiers

SYNOPSIS
#include <openssl/asn1.h>
ASN1_OBJECT *
d2i_ASN1_OBJECT(ASN1_OBJECT **val_out, unsigned char **der_in, long length);
int
i2d_ASN1_OBJECT(const ASN1_OBJECT *val_in, unsigned char **der_out);

DESCRIPTION
These functions decode and encode ASN.1 object identifiers. For details about the semantics, examples, caveats, and bugs, see ASN1_item_d2i(3).

The LibreSSL implementation of d2i_ASN1_OBJECT() always calls ASN1_OBJECT_free(3) if an existing object is passed in via val_out and it always creates a new object from scratch. Other implementations may attempt to reuse an existing object, which is fragile and prone to bugs. Consequently, always passing NULL for the val_out argument is recommended.

The objects returned from d2i_ASN1_OBJECT() and the data contained in them are always marked as dynamically allocated, so when they are no longer needed, ASN1_OBJECT_free(3) can be called on them.

RETURN VALUES
d2i_ASN1_OBJECT() returns a pointer to the new ASN1_OBJECT object or NULL if an error occurs. With other implementations, it might return a pointer to the reused ASN1_OBJECT.

i2d_ASN1_OBJECT() returns the number of bytes successfully encoded or a value <= 0 if an error occurs.

SEE ALSO
a2d_ASN1_OBJECT(3), ASN1_item_d2i(3), ASN1_OBJECT_new(3), OBJ_nid2obj(3)

STANDARDS
ITU-T Recommendation X.690, also known as ISO/IEC 8825-1: Information technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER), section 8.19: Encoding of an object identifier value

HISTORY
d2i_ASN1_OBJECT() and i2d_ASN1_OBJECT() first appeared in SSLeay 0.5.1 and have been available since OpenBSD 2.4.

CAVEATS
d2i_ASN1_OBJECT() never sets the long and short names of the object, not even if the object identifier matches one that is built into the library. To find the names of an object identifier parsed from DER or BER input, call OBJ_obj2nid(3) on the returned object, and then OBJ_nid2sn(3) and OBJ_nid2ln(3) on the result.