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authorBoris Kolpackov <boris@codesynthesis.com>2021-01-14 14:31:27 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2021-01-14 14:31:27 +0200
commit8345d5eba80a11de363c8a96070316fdd6b6fd22 (patch)
tree933d2537c7545c3e28c75ce60a108bcfa7ccfd37
parentf91dcce80beb48bf8b444b472f4820a4ff2b33e5 (diff)
Pass /Zc:__cplusplus by default starting from VC 15.7 (GitHub issue #107)
This can be overridden by passing a variant of this option as part of the compiler mode options.
-rw-r--r--libbuild2/cxx/init.cxx11
-rw-r--r--libbuild2/depdb.hxx7
2 files changed, 15 insertions, 3 deletions
diff --git a/libbuild2/cxx/init.cxx b/libbuild2/cxx/init.cxx
index ad0dd05..e2d7343 100644
--- a/libbuild2/cxx/init.cxx
+++ b/libbuild2/cxx/init.cxx
@@ -189,6 +189,17 @@ namespace build2
if (!o.empty ())
prepend (move (o));
+ // Since VC 15.7 we can get a (more) accurate __cplusplus value if
+ // we ask for it with /Zc:__cplusplus:
+ //
+ // https://devblogs.microsoft.com/cppblog/msvc-now-correctly-reports-__cplusplus/
+ //
+ if (mj > 19 || (mj == 19 && mi >= 14))
+ {
+ if (!find_option_prefix ("/Zc:__cplusplus", mode))
+ prepend ("/Zc:__cplusplus");
+ }
+
break;
}
case compiler_class::gcc:
diff --git a/libbuild2/depdb.hxx b/libbuild2/depdb.hxx
index ecc1f38..abc2565 100644
--- a/libbuild2/depdb.hxx
+++ b/libbuild2/depdb.hxx
@@ -55,9 +55,10 @@ namespace build2
//
// If we assume that an update of the database also means an update of the
// target, then this "interrupted update" situation can be easily detected
- // by comparing the database and target modification timestamps. This is
- // also used to handle the dry-run mode where we essentially do the
- // interruption ourselves.
+ // by comparing the database and target modification timestamps: a valid
+ // up-to-date state will always have the target mtime greater or equal to
+ // the depdb mtime. This is also used to handle the dry-run mode where we
+ // essentially do the interruption ourselves.
//
struct LIBBUILD2_SYMEXPORT depdb_base
{