From a8c2fa28947960cce78d905ac9bbcb490ec78382 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 3 May 2019 15:04:46 +0200
Subject: Add config.{c,cxx}.std

These values override {c,cxx}.std specified at the project level. In
particular, this allows us to force a specific standard for all the
projects in a build configuration, for example:

b create: conf/,cc config.cxx=g++ config.cxx.std=experimental
---
 build2/cc/common.hxx |  4 ++--
 build2/cc/module.cxx | 19 +++++++++++++++++--
 2 files changed, 19 insertions(+), 4 deletions(-)

(limited to 'build2/cc')

diff --git a/build2/cc/common.hxx b/build2/cc/common.hxx
index dec71ed..19733cf 100644
--- a/build2/cc/common.hxx
+++ b/build2/cc/common.hxx
@@ -43,6 +43,7 @@ namespace build2
       const variable& config_x_id;      // <type>[-<variant>]
       const variable& config_x_version;
       const variable& config_x_target;
+      const variable& config_x_std;
       const variable& config_x_poptions;
       const variable& config_x_coptions;
       const variable& config_x_loptions;
@@ -53,6 +54,7 @@ namespace build2
       const variable& x_sys_lib_dirs; // System library search directories.
       const variable& x_sys_inc_dirs; // System header search directories.
 
+      const variable& x_std;
       const variable& x_poptions;
       const variable& x_coptions;
       const variable& x_loptions;
@@ -87,8 +89,6 @@ namespace build2
       const variable& x_preprocessed; // x.preprocessed
       const variable* x_symexport;    // x.features.symexport
 
-      const variable& x_std;
-
       const variable& x_id;
       const variable& x_id_type;
       const variable& x_id_variant;
diff --git a/build2/cc/module.cxx b/build2/cc/module.cxx
index 1e3806a..7527da2 100644
--- a/build2/cc/module.cxx
+++ b/build2/cc/module.cxx
@@ -286,9 +286,24 @@ namespace build2
       const compiler_info& ci (*ci_);
       const target_triplet& tt (cast<target_triplet> (rs[x_target]));
 
-      // Translate x_std value (if any) to the compiler option(s) (if any).
+      // config.x.std overrides x.std
       //
-      tstd = translate_std (ci, rs, cast_null<string> (rs[x_std]));
+      {
+        lookup l (config::omitted (rs, config_x_std).first);
+
+        const string* v;
+        if (l.defined ())
+        {
+          v = cast_null<string> (l);
+          rs.assign (x_std) = v;
+        }
+        else
+          v = cast_null<string> (rs[x_std]);
+
+        // Translate x_std value (if any) to the compiler option(s) (if any).
+        //
+        tstd = translate_std (ci, rs, v);
+      }
 
       // Extract system header/library search paths from the compiler and
       // determine if we need any additional search paths.
-- 
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