README.md
1Adding new libraries
2====================
3
4When adding a new sub-library to OpenSSL, assign it a library number
5`ERR_LIB_XXX`, define a macro `XXXerr()` (both in `err.h`), add its
6name to `ERR_str_libraries[]` (in `crypto/err/err.c`), and add
7`ERR_load_XXX_strings()` to the `ERR_load_crypto_strings()` function
8(in `crypto/err/err_all.c`). Finally, add an entry:
9
10 L XXX xxx.h xxx_err.c
11
12to `crypto/err/openssl.ec`, and add `xxx_err.c` to the `Makefile`.
13Running make errors will then generate a file `xxx_err.c`, and
14add all error codes used in the library to `xxx.h`.
15
16Additionally the library include file must have a certain form.
17Typically it will initially look like this:
18
19 #ifndef HEADER_XXX_H
20 #define HEADER_XXX_H
21
22 #ifdef __cplusplus
23 extern "C" {
24 #endif
25
26 /* Include files */
27
28 #include <openssl/bio.h>
29 #include <openssl/x509.h>
30
31 /* Macros, structures and function prototypes */
32
33
34 /* BEGIN ERROR CODES */
35
36The `BEGIN ERROR CODES` sequence is used by the error code
37generation script as the point to place new error codes, any text
38after this point will be overwritten when make errors is run.
39The closing `#endif` etc will be automatically added by the script.
40
41The generated C error code file `xxx_err.c` will load the header
42files `stdio.h`, `openssl/err.h` and `openssl/xxx.h` so the
43header file must load any additional header files containing any
44definitions it uses.
45
46Adding new error codes
47======================
48
49Instead of manually adding error codes into `crypto/err/openssl.txt`,
50it is recommended to leverage `make update` for error code generation.
51The target will process relevant sources and generate error codes for
52any *used* error codes.
53
54If an error code is added manually into `crypto/err/openssl.txt`,
55subsequent `make update` has no effect.
56
