Constify i2t_ASN1_OBJECT, i2d_ASN1_OBJECT, i2a_ASN1_OBJECT.

[openssl.git] / doc / crypto / OBJ_nid2obj.pod

diff --git a/doc/crypto/OBJ_nid2obj.pod b/doc/crypto/OBJ_nid2obj.pod
index ac34a40225cbb8763594e1fd8f6ad190a812862f..3ada6679cf92b7d47e68e1532a562cdaa7a4ebbb 100644 (file)
--- a/doc/crypto/OBJ_nid2obj.pod
+++ b/doc/crypto/OBJ_nid2obj.pod
@@ -2,17 +2,19 @@
 
 =head1 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
+i2t_ASN1_OBJECT,
+OBJ_length, OBJ_get0_data, 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
 
 =head1 SYNOPSIS
 
  #include <openssl/objects.h>
 
- ASN1_OBJECT * OBJ_nid2obj(int n);
- const char *  OBJ_nid2ln(int n);
- const char *  OBJ_nid2sn(int n);
+ 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);
@@ -20,13 +22,15 @@ functions
 
  int OBJ_txt2nid(const char *s);
 
- ASN1_OBJECT * OBJ_txt2obj(const char *s, int no_name);
+ 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 i2t_ASN1_OBJECT(char *buf, int buf_len, const ASN1_OBJECT *a);
 
- int OBJ_create(const char *oid,const char *sn,const char *ln);
+ 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);
 
  size_t OBJ_length(const ASN1_OBJECT *obj);
  const unsigned char *OBJ_get0_data(const ASN1_OBJECT *obj);
@@ -41,6 +45,12 @@ Deprecated:
 
 The ASN1 object utility functions process ASN1_OBJECT structures which are
 a representation of the ASN1 OBJECT IDENTIFIER (OID) type.
+For convenience, OIDs are usually represented in source code as numeric
+identifiers, or B<NID>s.  OpenSSL has an internal table of OIDs that
+are generated when the library is built, and their corresponding NIDs
+are available as defined constants.  For the functions below, application
+code should treat all returned values -- OIDs, NIDs, or names -- as
+constants.
 
 OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID B<n> to
 an ASN1_OBJECT structure, its long name and its short name respectively,
@@ -66,6 +76,8 @@ if the object has a long or short name then that will be used, otherwise
 the numerical form will be used. If B<no_name> is 1 then the numerical
 form will always be used.
 
+i2t_ASN1_OBJECT() is the same as OBJ_obj2txt() with the B<no_name> set to zero.
+
 OBJ_cmp() compares B<a> to B<b>. If the two are identical 0 is returned.
 
 OBJ_dup() returns a copy of B<o>.
@@ -117,6 +129,10 @@ exists for a particular algorithm). As a result they B<cannot> be encoded or
 decoded as part of ASN.1 structures. Applications can determine if there
 is a corresponding OBJECT IDENTIFIER by checking OBJ_length() is not zero.
 
+These functions cannot return B<const> because an B<ASN1_OBJECT> can
+represent both an internal, constant, OID and a dynamically-created one.
+The latter cannot be constant because it needs to be freed after use.
+
 =head1 EXAMPLES
 
 Create an object for B<commonName>:
@@ -133,6 +149,7 @@ 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);