1Notes on the source code 2======================== 3 4The mechanism to generate the system error codes is delicate and 5fragile, but it's the best I could come up with that supports 6cross-compilation and dynamic self-configuration. Here is how it 7works: 8 91. Generate list of supported system error codes. 10 11mkerrcodes1.awk generates a list of supported system error codes from 12errnos.in. Each entry in the list is protected with #ifdef/#endif, 13and contains a GPG_ERR_* marker. The list is stored in "_mkerrcodes.h". 14 152. The HOST cpp is run on _mkerrcodes.h. This evaluates the known 16system error macros to something (may be a number, maybe a constant 17expression as on the GNU/Hurd), suppressing the unknown ones. The 18output is piped into step 3. 19 203. The cpp output is filtered with grep for only those lines which 21contain a GPG_ERR_* marker. The output is piped into step 4. 22 234. The filtered output is processed by mkerrcodes.awk, which produces 24a table of constant expressions plus GPG_ERR_* code string symbols in 25a format suitable for the C program mkerrcodes.c. At this point we 26are crossing our fingers that the constant expressions produced by the 27system do not contain GPG_ERR_* markers. The output is stored in 28mkerrcodes.h. 29 305. The file mkerrcodes.h is included by mkerrcodes.c, which is 31compiled to a binary executable on the BUILD system. At this point we 32are crossing our fingers that the constant expressions produced by the 33system do not depend on the build platform anymore. The output is 34post-processed by mkerrcodes2.awk and stored in "code-from-errno.h", 35which is subsequently used in the library. 36 37-- Marcus 38 39 Copyright 2006 g10 Code GmbH 40 41 This file is free software; as a special exception the author gives 42 unlimited permission to copy and/or distribute it, with or without 43 modifications, as long as this notice is preserved. 44 45 This file is distributed in the hope that it will be useful, but 46 WITHOUT ANY WARRANTY, to the extent permitted by law; without even the 47 implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 48