Document hermetic build configuration support

1 files changed, 10 insertions, 0 deletions

diff --git a/libbuild2/functions-process.cxx b/libbuild2/functions-process.cxx
index 0870874..4be5149 100644
--- a/libbuild2/functions-process.cxx
+++ b/libbuild2/functions-process.cxx
@@ -414,6 +414,11 @@ namespace build2
     //
     // Run builtin or external program and return trimmed stdout.
     //
+    // Note that if the result of executing the program can be affected by
+    // environment variables and this result can in turn affect the build
+    // result, then such variables should be reported with the
+    // config.environment directive.
+    //
     // Note that this function is not pure.
     //
     f.insert (".run", false) += [](const scope* s, names args)
@@ -435,6 +440,11 @@ namespace build2
     // (as a whole) against <pat> and, if successful, returned, optionally
     // processed with <fmt>, as an element of a list.
     //
+    // Note that if the result of executing the program can be affected by
+    // environment variables and this result can in turn affect the build
+    // result, then such variables should be reported with the
+    // config.environment directive.
+    //
     // Note that this function is not pure.
     //
     {