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Diffstat (limited to 'config_host/README')
| -rw-r--r-- | config_host/README | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/config_host/README b/config_host/README new file mode 100644 index 000000000000..fd58b64045bb --- /dev/null +++ b/config_host/README @@ -0,0 +1,24 @@ +These are configuration files for various features as detected by configure. + +Include only those files you need (in order to reduce rebuilds when a setting changes). + +Settings here are only C/C++ #define directives, so they apply only to C/C++ source, +not to Makefiles. + + + +Adding a new setting: +===================== + +- do AC_DEFINE(HAVE_FOO) in configure.ac when a setting should be set +- choose the proper config/config_xxx.h file to use + - if it is a global setting (such as availability of a compiler feature), + use config/config_global.h + - otherwise check if there is a matching config/config_hxx.h file + - if none matches, add a new one: + - add config/config_xxx.h.in here, with just #ifndef include guard + - add AC_CONFIG_HEADERS([config/config_xxx.h]) next to the others + in configure.ac + - add config_hxx.h to config/.gitignore +- add #undef HAVE_FOO to the config/config_hxx.h , possibly with a comment +- add #include <config_xxx.h> before any #ifdef HAVE_XXX in a source file |