* cppinit.c (struct lang_flags): Rename trigraphs std.
(set_lang): Update.
* cpplib.h (struct cpp_options): New member std.
* cppmacro.c (_cpp_builtin_macro_text): Use std.
(collect_args): Flag whether to swallow a possible future
comma pasted with varargs.
(replace_args): Use this flag.
* doc/cpp.texi: Update varargs extension documentation.
testsuite:
* gcc.dg/cpp/vararg3.c, gcc.dg/cpp/vararg4.c: New tests.
From-SVN: r56077
+2002-08-06 Neil Booth <neil@daikokuya.co.uk>
+
+ * cppinit.c (struct lang_flags): Rename trigraphs std.
+ (set_lang): Update.
+ * cpplib.h (struct cpp_options): New member std.
+ * cppmacro.c (_cpp_builtin_macro_text): Use std.
+ (collect_args): Flag whether to swallow a possible future
+ comma pasted with varargs.
+ (replace_args): Use this flag.
+ * doc/cpp.texi: Update varargs extension documentation.
+
2002-08-06 Jakub Jelinek <jakub@redhat.com>
* config/i386/mmintrin.h (__m64): Make the type 64-bit aligned.
char c99;
char cplusplus;
char extended_numbers;
- char trigraphs;
+ char std;
char dollars_in_ident;
char cplusplus_comments;
char digraphs;
/* ??? Enable $ in identifiers in assembly? */
static const struct lang_flags lang_defaults[] =
-{ /* c99 c++ xnum trig dollar c++comm digr */
+{ /* c99 c++ xnum std dollar c++comm digr */
/* GNUC89 */ { 0, 0, 1, 0, 1, 1, 1 },
/* GNUC99 */ { 1, 0, 1, 0, 1, 1, 1 },
/* STDC89 */ { 0, 0, 0, 1, 0, 0, 0 },
CPP_OPTION (pfile, c99) = l->c99;
CPP_OPTION (pfile, cplusplus) = l->cplusplus;
CPP_OPTION (pfile, extended_numbers) = l->extended_numbers;
- CPP_OPTION (pfile, trigraphs) = l->trigraphs;
+ CPP_OPTION (pfile, std) = l->std;
+ CPP_OPTION (pfile, trigraphs) = l->std;
CPP_OPTION (pfile, dollars_in_ident) = l->dollars_in_ident;
CPP_OPTION (pfile, cplusplus_comments) = l->cplusplus_comments;
CPP_OPTION (pfile, digraphs) = l->digraphs;
/* Nonzero for the 1999 C Standard, including corrigenda and amendments. */
unsigned char c99;
+ /* Nonzero if we are conforming to a specific C or C++ standard. */
+ unsigned char std;
+
/* Nonzero means give all the error messages the ANSI standard requires. */
unsigned char pedantic;
enum c_lang lang = CPP_OPTION (pfile, lang);
if (CPP_IN_SYSTEM_HEADER (pfile)
&& CPP_OPTION (pfile, stdc_0_in_system_headers)
- && !(lang == CLK_STDC89 || lang == CLK_STDC94
- || lang == CLK_STDC99)) /* || lang == CLK_CXX98 ? */
+ && !CPP_OPTION (pfile,std))
number = 0;
else
number = 1;
if (argc == 1 && macro->paramc == 0 && args[0].count == 0)
argc = 0;
if (_cpp_arguments_ok (pfile, macro, node, argc))
- return base_buff;
+ {
+ /* GCC has special semantics for , ## b where b is a varargs
+ parameter: we remove the comma if b was omitted entirely.
+ If b was merely an empty argument, the comma is retained.
+ If the macro takes just one (varargs) parameter, then we
+ retain the comma only if we are standards conforming.
+
+ If FIRST is NULL replace_args () swallows the comma. */
+ if (macro->variadic && (argc < macro->paramc
+ || (argc == 1 && args[0].count == 0
+ && !CPP_OPTION (pfile, std))))
+ args[macro->paramc - 1].first = NULL;
+ return base_buff;
+ }
}
/* An error occurred. */
count = arg->count, from = arg->first;
if (dest != first)
{
- /* GCC has special semantics for , ## b where b is a
- varargs parameter: the comma disappears if b was
- given no actual arguments (not merely if b is an
- empty argument); otherwise the paste flag is removed. */
if (dest[-1]->type == CPP_COMMA
&& macro->variadic
&& src->val.arg_no == macro->paramc)
{
- if (count == 0)
+ /* Swallow a pasted comma if from == NULL, otherwise
+ drop the paste flag. */
+ if (from == NULL)
dest--;
else
paste_flag = dest - 1;
@end example
@noindent
-using this extension. You cannot use @code{__VA_ARGS__} and this
+using this extension. You cannot use @code{@w{__VA_ARGS__}} and this
extension in the same macro.
You can have named arguments as well as variable arguments in a variadic
@expansion{} fprintf(stderr, "success!\n");
@end example
+@noindent
+The above explanation is ambiguous about the case where the only macro
+parameter is a variable arguments parameter, as it is meaningless to
+try to distinguish whether no argument at all is an empty argument or
+a missing argument. In this case the C99 standard is clear that the
+comma must remain, however the existing GCC extension used to swallow
+the comma. So CPP retains the comma when conforming to a specific C
+standard, and drops it otherwise.
+
C99 mandates that the only place the identifier @code{@w{__VA_ARGS__}}
can appear is in the replacement list of a variadic macro. It may not
be used as a macro name, macro argument name, or within a different type
+2002-08-06 Neil Booth <neil@daikokuya.co.uk>
+
+ * gcc.dg/cpp/vararg3.c, gcc.dg/cpp/vararg4.c: New tests.
+
2002-08-06 Jakub Jelinek <jakub@redhat.com>
* g++.dg/abi/bitfield3.C: New test.
--- /dev/null
+/* Copyright (C) 2002 Free Software Foundation, Inc. */
+
+/* { dg-do preprocess } */
+/* { dg-options "-std=c99" } */
+
+/* Source: Neil Booth, 6 Aug 2002.
+
+ Tests that we DTRT with varargs commas for a single-parameter macro
+ when in standards-conforming mode. */
+
+#define f(...) , ## __VA_ARGS__
+
+/* The comma from f's expansion should be retained (standards
+ conforming mode only). Tests that it isn't in non-standards mode
+ include macro8.c and vararg1.c. */
+#if 2 f() 3 /* { dg-bogus "missing binary operator" } */
+#endif
--- /dev/null
+/* Copyright (C) 2002 Free Software Foundation, Inc. */
+
+/* { dg-do preprocess } */
+/* { dg-options -std=gnu99 } */
+
+/* Source: Neil Booth, 6 Aug 2002.
+
+ Tests that we DTRT with varargs commas. */
+
+#define g(a, ...) a , ## __VA_ARGS__
+
+/* The comma from g's expansion should be retained. */
+#if g (2, ) 3 /* { dg-bogus "missing binary operator" } */
+#endif
projects / gcc.git / commitdiff