Add build.driver variable with build system driver path (argv[0])

4 files changed, 13 insertions, 3 deletions

diff --git a/build2/b.cxx b/build2/b.cxx
index d800605..a652c97 100644
--- a/build2/b.cxx
+++ b/build2/b.cxx
@@ -161,7 +161,8 @@ main (int argc, char* argv[])
 
     // Global initializations.
     //
-    init (ops.verbose_specified ()
+    init (argv[0],
+          ops.verbose_specified ()
           ? ops.verbose ()
           : ops.V () ? 3 : ops.v () ? 2 : ops.q () ? 0 : 1);
 
diff --git a/build2/context.cxx b/build2/context.cxx
index c783832..6d39da2 100644
--- a/build2/context.cxx
+++ b/build2/context.cxx
@@ -238,6 +238,8 @@ namespace build2
       v.insert<string> ("extension", variable_visibility::target);
     }
 
+    gs.assign<path> ("build.driver") = argv0;
+
     gs.assign<dir_path> ("build.work") = work;
     gs.assign<dir_path> ("build.home") = home;
 
diff --git a/build2/utility b/build2/utility
index 56e0c47..7c30395 100644
--- a/build2/utility
+++ b/build2/utility
@@ -83,6 +83,10 @@ namespace build2
   next_word (const string&, size_t n, size_t& b, size_t& e,
              char d1 = ' ', char d2 = '\0');
 
+  // Build system driver recall path (argv[0]).
+  //
+  extern path argv0;
+
   // Work/home directories (must be initialized in main()) and relative path
   // calculation.
   //
@@ -476,7 +480,7 @@ namespace build2
   // Should be called early in main() once.
   //
   void
-  init (uint16_t verbosity);
+  init (const char* argv0, uint16_t verbosity);
 }
 
 #include <build2/utility.ixx>
diff --git a/build2/utility.cxx b/build2/utility.cxx
index ca6b239..4b68edb 100644
--- a/build2/utility.cxx
+++ b/build2/utility.cxx
@@ -89,6 +89,7 @@ namespace build2
     return l;
   }
 
+  path argv0;
   dir_path work;
   dir_path home;
   const dir_path* relative_base = &work;
@@ -505,8 +506,10 @@ namespace build2
   bool exception_unwinding_dtor = false;
 
   void
-  init (uint16_t v)
+  init (const char* a0, uint16_t v)
   {
+    argv0 = path (a0);
+
     // Diagnostics verbosity.
     //
     verb = v;