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Diffstat (limited to 'comm/third_party/libgpg-error/src/README')
-rw-r--r-- | comm/third_party/libgpg-error/src/README | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/comm/third_party/libgpg-error/src/README b/comm/third_party/libgpg-error/src/README new file mode 100644 index 0000000000..c415983598 --- /dev/null +++ b/comm/third_party/libgpg-error/src/README @@ -0,0 +1,47 @@ +Notes on the source code +======================== + +The mechanism to generate the system error codes is delicate and +fragile, but it's the best I could come up with that supports +cross-compilation and dynamic self-configuration. Here is how it +works: + +1. Generate list of supported system error codes. + +mkerrcodes1.awk generates a list of supported system error codes from +errnos.in. Each entry in the list is protected with #ifdef/#endif, +and contains a GPG_ERR_* marker. The list is stored in "_mkerrcodes.h". + +2. The HOST cpp is run on _mkerrcodes.h. This evaluates the known +system error macros to something (may be a number, maybe a constant +expression as on the GNU/Hurd), suppressing the unknown ones. The +output is piped into step 3. + +3. The cpp output is filtered with grep for only those lines which +contain a GPG_ERR_* marker. The output is piped into step 4. + +4. The filtered output is processed by mkerrcodes.awk, which produces +a table of constant expressions plus GPG_ERR_* code string symbols in +a format suitable for the C program mkerrcodes.c. At this point we +are crossing our fingers that the constant expressions produced by the +system do not contain GPG_ERR_* markers. The output is stored in +mkerrcodes.h. + +5. The file mkerrcodes.h is included by mkerrcodes.c, which is +compiled to a binary executable on the BUILD system. At this point we +are crossing our fingers that the constant expressions produced by the +system do not depend on the build platform anymore. The output is +post-processed by mkerrcodes2.awk and stored in "code-from-errno.h", +which is subsequently used in the library. + +-- Marcus + + Copyright 2006 g10 Code GmbH + + This file is free software; as a special exception the author gives + unlimited permission to copy and/or distribute it, with or without + modifications, as long as this notice is preserved. + + This file is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY, to the extent permitted by law; without even the + implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |