OBJ_nid2obj(3)

     NAME
          OBJ_nid2obj, OBJ_nid2ln, OBJ_nid2sn, OBJ_obj2nid,
          OBJ_txt2nid, OBJ_ln2nid, OBJ_sn2nid, OBJ_cmp, OBJ_dup,
          OBJ_txt2obj, OBJ_obj2txt, OBJ_create, OBJ_cleanup - ASN1
          object utility functions

     SYNOPSIS
           ASN1_OBJECT * OBJ_nid2obj(int n);
           const char *  OBJ_nid2ln(int n);
           const char *  OBJ_nid2sn(int n);

           int OBJ_obj2nid(const ASN1_OBJECT *o);
           int OBJ_ln2nid(const char *ln);
           int OBJ_sn2nid(const char *sn);

           int OBJ_txt2nid(const char *s);

           ASN1_OBJECT * OBJ_txt2obj(const char *s, int no_name);
           int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name);

           int OBJ_cmp(const ASN1_OBJECT *a,const ASN1_OBJECT *b);
           ASN1_OBJECT * OBJ_dup(const ASN1_OBJECT *o);

           int OBJ_create(const char *oid,const char *sn,const char *ln);
           void OBJ_cleanup(void);


     DESCRIPTION
          The ASN1 object utility functions process ASN1_OBJECT
          structures which are a representation of the ASN1 OBJECT
          IDENTIFIER (OID) type.

          OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID
          n to an ASN1_OBJECT structure, its long name and its short
          name respectively, or NULL is an error occurred.

          OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the
          corresponding NID for the object o, the long name <ln> or
          the short name <sn> respectively or NID_undef if an error
          occurred.

          OBJ_txt2nid() returns NID corresponding to text string <s>.
          s can be a long name, a short name or the numerical
          respresentation of an object.

          OBJ_txt2obj() converts the text string s into an ASN1_OBJECT
          structure.  If no_name is 0 then long names and short names
          will be interpreted as well as numerical forms. If no_name
          is 1 only the numerical form is acceptable.

          OBJ_obj2txt() converts the ASN1_OBJECT a into a textual
          representation.  The representation is written as a null
          terminated string to buf at most buf_len bytes are written,
          truncating the result if necessary.  The total amount of
          space required is returned. If no_name is 0 then if the
          object has a long or short name then that will be used,
          otherwise the numerical form will be used. If no_name is 1
          then the numerical form will always be used.

          OBJ_cmp() compares a to b. If the two are identical 0 is
          returned.

          OBJ_dup() returns a copy of o.

          OBJ_create() adds a new object to the internal table. oid is
          the numerical form of the object, sn the short name and ln
          the long name. A new NID is returned for the created object.

          OBJ_cleanup() cleans up OpenSSLs internal object table: this
          should be called before an application exits if any new
          objects were added using OBJ_create().

     NOTES
          Objects in OpenSSL can have a short name, a long name and a
          numerical identifier (NID) associated with them. A standard
          set of objects is represented in an internal table. The
          appropriate values are defined in the header file objects.h.

          For example the OID for commonName has the following
          definitions:

           #define SN_commonName                   "CN"
           #define LN_commonName                   "commonName"
           #define NID_commonName                  13

          New objects can be added by calling OBJ_create().

          Table objects have certain advantages over other objects:
          for example their NIDs can be used in a C language switch
          statement. They are also static constant structures which
          are shared: that is there is only a single constant
          structure for each table object.

          Objects which are not in the table have the NID value
          NID_undef.

          Objects do not need to be in the internal tables to be
          processed, the functions OBJ_txt2obj() and OBJ_obj2txt() can
          process the numerical form of an OID.

     EXAMPLES
          Create an object for commonName:

           ASN1_OBJECT *o;
           o = OBJ_nid2obj(NID_commonName);

          Check if an object is commonName

           if (OBJ_obj2nid(obj) == NID_commonName)
                  /* Do something */

          Create a new NID and initialize an object from it:

           int new_nid;
           ASN1_OBJECT *obj;
           new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier");

           obj = OBJ_nid2obj(new_nid);

          Create a new object directly:

           obj = OBJ_txt2obj("1.2.3.4", 1);


     BUGS
          OBJ_obj2txt() is awkward and messy to use: it doesn't follow
          the convention of other OpenSSL functions where the buffer
          can be set to NULL to determine the amount of data that
          should be written.  Instead buf must point to a valid buffer
          and buf_len should be set to a positive value. A buffer
          length of 80 should be more than enough to handle any OID
          encountered in practice.

     RETURN VALUES
          OBJ_nid2obj() returns an ASN1_OBJECT structure or NULL is an
          error occurred.

          OBJ_nid2ln() and OBJ_nid2sn() returns a valid string or NULL
          on error.

          OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and OBJ_txt2nid()
          return a NID or NID_undef on error.

     SEE ALSO
          ERR_get_error(3)

     HISTORY
          TBA