Re: Still a lot of C++ files getting "fixed"

[Zack Weinberg <zack at wolery dot cumb dot org>]

On Wed, Jan 26, 2000 at 12:08:49PM -0500, Kaveh R. Ghazi wrote:
>  > From: Zack Weinberg <zack@wolery.cumb.org>
>  >  
>  > > So it is not a great leap to do the same for -ansi.  It can be
>  > > pedantically ANSI for user code, and more relaxed about system
>  > > headers, IMHO.
>  >  
>  > If we're going to go down this road, we might consider also
>  > disabling pedantic complaints about a token after #else/#endif in
>  > the system headers.  On SunOS, at least half the files modified
>  > have only that change.
>  > zw
> 
> Sounds like a good idea.
> 
> Are you volunteering to write a patch to cccp/cpplib? :-)

I'd be happy to :)

Here is a completely untested patch for tokens after #else/#endif.
I'll commit the cpplib half of it after testing.  Who owns cccp?

The C++ comments issue will be trickier - it looks like we never emit
warnings for them, just recognize or don't recognize.  That's wrong;
at the very least, C89 mode -pedantic needs to give warnings.
I need to think about what the appropriate behavior is.

zw

===================================================================
Index: cccp.c
--- cccp.c	2000/01/14 00:46:56	1.94
+++ cccp.c	2000/01/26 19:07:17
@@ -7842,7 +7842,7 @@ skip_if_group (ip, any, op)
 	    break;
 	  case T_ELSE:
 	  case T_ENDIF:
-	    if (pedantic && if_stack != save_if_stack)
+	    if (if_stack != save_if_stack)
 	      validate_else (bp, endb);
 	  case T_ELIF:
 	    if (if_stack == instack[indepth].if_stack) {
@@ -7922,11 +7922,7 @@ do_else (buf, limit, op, keyword)
 {
   FILE_BUF *ip = &instack[indepth];
 
-  if (pedantic) {
-    SKIP_WHITE_SPACE (buf);
-    if (buf != limit)
-      pedwarn ("text following `#else' violates ANSI standard");
-  }
+  validate_else (buf, limit);
 
   if (if_stack == instack[indepth].if_stack) {
     error ("`#else' not within a conditional");
@@ -7968,11 +7964,7 @@ do_endif (buf, limit, op, keyword)
      FILE_BUF *op;
      struct directive *keyword ATTRIBUTE_UNUSED;
 {
-  if (pedantic) {
-    SKIP_WHITE_SPACE (buf);
-    if (buf != limit)
-      pedwarn ("text following `#endif' violates ANSI standard");
-  }
+  validate_else (buf, limit);
 
   if (if_stack == instack[indepth].if_stack)
     error ("unbalanced `#endif'");
@@ -8020,16 +8012,18 @@ do_endif (buf, limit, op, keyword)
   return 0;
 }
 
-/* When an #else or #endif is found while skipping failed conditional,
-   if -pedantic was specified, this is called to warn about text after
-   the directive name.  P points to the first char after the directive
-   name.  */
+/* Issue -pedantic warning for text which is not a comment following
+   an #else or #endif.  Do not warn in system headers, as this is harmless
+   and very common on old systems.  */
 
 static void
 validate_else (p, limit)
      register const U_CHAR *p;
      register const U_CHAR *limit;
 {
+  if (!pedantic || instack[indepth].system_header_p)
+    return;
+
   /* Advance P over whitespace and comments.  */
   while (1) {
     while (*p == '\\' && p[1] == '\n')
===================================================================
Index: cpplib.c
--- cpplib.c	2000/01/19 23:47:13	1.99
+++ cpplib.c	2000/01/26 19:07:17
@@ -2008,7 +2008,7 @@ consider_directive_while_skipping (pfile
 	    return 0;
 
 	case T_ELSE:
-	    if (CPP_PEDANTIC (pfile) && pfile->if_stack != stack)
+	    if (pfile->if_stack != stack)
 	      validate_else (pfile, "#else");
 	    /* fall through */
 	case T_ELIF:
@@ -2024,7 +2024,7 @@ consider_directive_while_skipping (pfile
 	      }
 
 	    case T_ENDIF:
-		if (CPP_PEDANTIC (pfile) && pfile->if_stack != stack)
+		if (pfile->if_stack != stack)
 		  validate_else (pfile, "#endif");
 
 		if (pfile->if_stack == stack)
@@ -2140,8 +2140,7 @@ do_else (pfile, keyword)
 {
   cpp_buffer *ip = CPP_BUFFER (pfile);
 
-  if (CPP_PEDANTIC (pfile))
-    validate_else (pfile, "#else");
+  validate_else (pfile, "#else");
   skip_rest_of_line (pfile);
 
   if (pfile->if_stack == CPP_BUFFER (pfile)->if_stack) {
@@ -2180,8 +2179,7 @@ do_endif (pfile, keyword)
      cpp_reader *pfile;
      const struct directive *keyword ATTRIBUTE_UNUSED;
 {
-  if (CPP_PEDANTIC (pfile))
-    validate_else (pfile, "#endif");
+  validate_else (pfile, "#endif");
   skip_rest_of_line (pfile);
 
   if (pfile->if_stack == CPP_BUFFER (pfile)->if_stack)
@@ -2226,19 +2224,20 @@ do_endif (pfile, keyword)
   return 0;
 }
 
-/* When an #else or #endif is found while skipping failed conditional,
-   if -pedantic was specified, this is called to warn about text after
-   the command name.  P points to the first char after the command name.  */
+/* Issue -pedantic warning for text which is not a comment following
+   an #else or #endif.  Do not warn in system headers, as this is harmless
+   and very common on old systems.  */
 
 static void
 validate_else (pfile, directive)
      cpp_reader *pfile;
      const char *directive;
 {
-  int c;
+  if (! CPP_PEDANTIC (pfile) || CPP_BUFFER (pfile)->system_header_p)
+    return;
+
   cpp_skip_hspace (pfile);
-  c = PEEKC ();
-  if (c != EOF && c != '\n')
+  if (PEEKC () != '\n')
     cpp_pedwarn (pfile,
 		 "text following `%s' violates ANSI standard", directive);
 }