Initial connect BIO docs.

[oweals/openssl.git] / doc / crypto / err.pod

diff --git a/doc/crypto/err.pod b/doc/crypto/err.pod
index 029899769e79b819c2afb8946adabb88a99976aa..b824c92b57c3172c1b42c3791bc5408e8f6d9ab0 100644 (file)
--- a/doc/crypto/err.pod
+++ b/doc/crypto/err.pod
@@ -2,7 +2,7 @@
 
 =head1 NAME
 
 
 =head1 NAME
 

-err - Error codes
+err - error codes

 
 =head1 SYNOPSIS
 
 
 =head1 SYNOPSIS
 


@@ -71,7 +71,7 @@ See L<ERR_put_error(3)> if you want to record error codes in the
 OpenSSL error system from within your application.
 
 The remainder of this section is of interest only if you want to add
 OpenSSL error system from within your application.
 
 The remainder of this section is of interest only if you want to add

-new functionality to OpenSSL.
+new error codes to OpenSSL or add error codes from external libraries.

 
 =head2 Reporting errors
 
 
 =head2 Reporting errors
 


@@ -84,10 +84,24 @@ descriptions. For example, the function ssl23_read() reports a
 
  SSLerr(SSL_F_SSL23_READ, SSL_R_SSL_HANDSHAKE_FAILURE);
 
 
  SSLerr(SSL_F_SSL23_READ, SSL_R_SSL_HANDSHAKE_FAILURE);
 

+Function and reason codes should consist of upper case characters,
+numbers and underscores only. The error file generation script translates
+function codes into function names by looking in the header files
+for an appropriate function name, if none is found it just uses
+the capitalized form such as "SSL23_READ" in the above example.
+
+The trailing section of a reason code (after the "_R_") is translated
+into lower case and underscores changed to spaces.
+

 When you are using new function or reason codes, run B<make errors>.
 The necessary B<#define>s will then automatically be added to the
 sub-library's header file.
 
 When you are using new function or reason codes, run B<make errors>.
 The necessary B<#define>s will then automatically be added to the
 sub-library's header file.
 

+Although a library will normally report errors using its own specific
+XXXerr macro, another library's macro can be used. This is normally
+only done when a library wants to include ASN1 code which must use
+the ASN1err() macro.
+

 =head2 Adding new libraries
 
 When adding a new sub-library to OpenSSL, assign it a library number
 =head2 Adding new libraries
 
 When adding a new sub-library to OpenSSL, assign it a library number


@@ -102,6 +116,47 @@ to B<crypto/err/openssl.ec>, and add B<xxx_err.c> to the Makefile.
 Running B<make errors> will then generate a file B<xxx_err.c>, and
 add all error codes used in the library to B<xxx.h>.
 
 Running B<make errors> will then generate a file B<xxx_err.c>, and
 add all error codes used in the library to B<xxx.h>.
 

+Additionally the library include file must have a certain form.
+Typically it will initially look like this:
+
+ #ifndef HEADER_XXX_H
+ #define HEADER_XXX_H
+
+ #ifdef __cplusplus
+ extern "C" {
+ #endif
+
+ /* Include files */
+
+ #include <openssl/bio.h>
+ #include <openssl/x509.h>
+
+ /* Macros, structures and function prototypes */
+
+
+ /* BEGIN ERROR CODES */
+
+The B<BEGIN ERROR CODES> sequence is used by the error code
+generation script as the point to place new error codes, any text
+after this point will be overwritten when B<make errors> is run.
+The closing #endif etc will be automatically added by the script.
+
+The generated C error code file B<xxx_err.c> will load the header
+files B<stdio.h>, B<openssl/err.h> and B<openssl/xxx.h> so the
+header file must load any additional header files containg any
+definitions it uses.
+
+=head1 USING ERROR CODES IN EXTERNAL LIBRARIES
+
+It is also possible to use OpenSSL's error code scheme in external
+libraries. The library needs to load its own codes and call the OpenSSL
+error code insertion script B<mkerr.pl> explicitly to add codes to
+the header file and generate the C error code file. This will normally
+be done if the external library needs to generate new ASN1 structures
+but it can also be used to add more general purpose error code handling.
+
+TBA more details
+

 =head1 INTERNALS
 
 The error queues are stored in a hash table with one B<ERR_STATE>
 =head1 INTERNALS
 
 The error queues are stored in a hash table with one B<ERR_STATE>