diff options
Diffstat (limited to 'config_host/README.md')
| -rw-r--r-- | config_host/README.md | 33 |
1 files changed, 16 insertions, 17 deletions
diff --git a/config_host/README.md b/config_host/README.md index 5dd2d5263481..af5030460d35 100644 --- a/config_host/README.md +++ b/config_host/README.md @@ -1,25 +1,24 @@ -These are configuration files for various features as detected by configure. +# C/C++ Configuration Created by configure Script + +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, +Settings here are only C/C++ `#define` directives, so they apply only to C/C++ source, not to Makefiles. +## Adding a New Setting: - -Adding a new setting: -===================== - -- do AC_DEFINE(HAVE_FOO) in configure.ac when a setting should be set -- choose the proper config_host/config_XXX.h file to use +- do `AC_DEFINE(HAVE_FOO)` in `configure.ac` when a setting should be set +- choose the proper `config_host/config_XXX.h` file to use - if it is a global setting (such as availability of a compiler feature), - use config_host/config_global.h - - otherwise check if there is a matching config_host/config_XXX.h file + use `config_host/config_global.h` + - otherwise check if there is a matching `config_host/config_XXX.h` file - if none matches, add a new one: - - add config_host/config_XXX.h.in here, with just #ifndef include guard - - add AC_CONFIG_HEADERS([config_host/config_XXX.h]) next to the others - in configure.ac -- add #define HAVE_FOO 0 to the config_host/config_XXX.h , possibly with a comment - (do not use #undef HAVE_FOO, unless the setting has more values than on/off) -- add #include <config_XXX.h> before any #if HAVE_FOO in a source file -- make sure you use #if HAVE_FOO for on/off settings, do not use #ifdef + - add `config_host/config_XXX.h.in` here, with just `#ifndef` include guard + - add `AC_CONFIG_HEADERS([config_host/config_XXX.h])` next to the others + in `configure.ac` +- add `#define HAVE_FOO 0` to the `config_host/config_XXX.h`, possibly with a comment + (do not use `#undef HAVE_FOO`, unless the setting has more values than on/off) +- add `#include <config_XXX.h>` before any #if `HAVE_FOO` in a source file +- make sure you use `#if HAVE_FOO` for on/off settings, do not use `#ifdef` |