libressl-a2d_ASN1_OBJECT(3)

libressl-a2d_ASN1_OBJECT3

Der content octets of an asn.1 object identifier

Usage

Crypto Library (libcrypto, -lcrypto)

#include <openssl/asn1.h>

int

a2d_ASN1_OBJECT(unsigned char *der_out, int olen, const char *val_in, int ilen);

Overview

a2d_ASN1_OBJECT() accepts an ASCII string val_in of ilen bytes and interprets it as the numerical form of an ASN.1 object identifier. It writes the content octets of the DER encoding of the object identifier to the buffer der_out which is olen bytes long. The identifier and length octets of the DER encoding are not written.

If ilen is -1, the strlen(3) of val_in is used instead.

If der_out is a NULL pointer, writing the content octets is skipped and only the return value is calculated.

Return values

a2d_ASN1_OBJECT() returns the number of content octets that were or would be written or 0 if ilen is 0, if val_in is not a valid representation of an object identifier, if memory allocation fails, or if the number of content octets would be larger than olen.

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

a2d_ASN1_OBJECT() first appeared in SSLeay 0.8.0 and has been available since OpenBSD 2.4.

From libressl 4.4.0-1 in Arch Linux 2026-11-01. Parsed by carta from the page's mdoc source.