Module Name: src
Committed By: rillig
Date: Mon Feb 22 21:14:15 UTC 2021
Modified Files:
src/usr.bin/make: var.c
Log Message:
make: document interaction between cmdline and global variables
Make prevents global variables from being or becoming visible when a
command line variable of the same name is already defined.
There is a double safety net here. Even if the call to Var_DeleteExpand
were removed, there would be no noticeable effect, other than one less
line in the debug log.
No functional change.
To generate a diff of this commit:
cvs rdiff -u -r1.831 -r1.832 src/usr.bin/make/var.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/usr.bin/make/var.c
diff -u src/usr.bin/make/var.c:1.831 src/usr.bin/make/var.c:1.832
--- src/usr.bin/make/var.c:1.831 Tue Feb 16 19:46:15 2021
+++ src/usr.bin/make/var.c Mon Feb 22 21:14:15 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: var.c,v 1.831 2021/02/16 19:46:15 rillig Exp $ */
+/* $NetBSD: var.c,v 1.832 2021/02/22 21:14:15 rillig Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1993
@@ -140,7 +140,7 @@
#include "metachar.h"
/* "@(#)var.c 8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: var.c,v 1.831 2021/02/16 19:46:15 rillig Exp $");
+MAKE_RCSID("$NetBSD: var.c,v 1.832 2021/02/22 21:14:15 rillig Exp $");
typedef enum VarFlags {
VFL_NONE = 0,
@@ -945,6 +945,14 @@ Var_SetWithFlags(GNode *scope, const cha
if (scope == SCOPE_GLOBAL) {
v = VarFind(name, SCOPE_CMDLINE, FALSE);
if (v != NULL) {
+ /*
+ * When there is a variable of the same name in the
+ * command line scope, the global variable would not
+ * be visible anywhere. Therefore there is no point
+ * in setting it at all.
+ *
+ * See 'scope == SCOPE_CMDLINE' below.
+ */
if (v->flags & VFL_FROM_CMD) {
DEBUG3(VAR, "%s:%s = %s ignored!\n",
scope->name, name, val);
@@ -966,6 +974,8 @@ Var_SetWithFlags(GNode *scope, const cha
* This var would normally prevent the same name being
* added to SCOPE_GLOBAL, so delete it from there if
* needed. Otherwise -V name may show the wrong value.
+ *
+ * See 'scope == SCOPE_GLOBAL' above.
*/
/* XXX: name is expanded for the second time */
Var_DeleteExpand(SCOPE_GLOBAL, name);
