[patch] PR 50134: improve docs for -Wmissing-prototypes and -Wmissing-declarations

[patch] PR 50134: improve docs for -Wmissing-prototypes and -Wmissing-declarations

[Jonathan Wakely]

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2012-06-01  Manuel López-Ibáñez  <manu@gcc.gnu.org>
            Jonathan Wakely  <jwakely.gcc@gmail.com>

        PR c++/50134
        * doc/invoke.texi (Warning Options): Explain purpose and differences
        between -Wmissing-prototypes and -Wmissing-declarations.

This patch tries to improve the docs to clarify the intent of these options.

The new wording isn't strictly accurate when it says that in C++ "all
function declarations provide prototypes" because C++ doesn't use the
term "prototype" at all, but I think it's clear what it means.

OK for trunk?

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diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 3ad07f3..eb582b3 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -4416,8 +4416,12 @@ This warning is also enabled by @option{-Wextra}.
 @opindex Wno-missing-prototypes
 Warn if a global function is defined without a previous prototype
 declaration.  This warning is issued even if the definition itself
-provides a prototype.  The aim is to detect global functions that 
-are not declared in header files.
+provides a prototype.  Use this option to detect global functions
+that do not have a matching prototype declaration in a header file.
+This option is not valid for C++ because all function declarations
+provide prototypes and a non-matching declaration will declare an
+overload rather than conflict with an earlier declaration.
+Use @option{-Wmissing-declarations} to detect missing declarations in C++.
 
 @item -Wmissing-declarations
 @opindex Wmissing-declarations
@@ -4425,7 +4429,9 @@ are not declared in header files.
 Warn if a global function is defined without a previous declaration.
 Do so even if the definition itself provides a prototype.
 Use this option to detect global functions that are not declared in
-header files.  In C++, no warnings are issued for function templates,
+header files.  In C, no warnings are issued for functions with previous
+non-prototype declarations; use @option{-Wmissing-prototype} to detect
+missing prototypes.  In C++, no warnings are issued for function templates,
 or for inline functions, or for functions in anonymous namespaces.
 
 @item -Wmissing-field-initializers

Re: [patch] PR 50134: improve docs for -Wmissing-prototypes and -Wmissing-declarations

[Jonathan Wakely]

For the record, Gaby approved this change (thanks, Gaby,) but his mail
didn't show up in the archives (gmail likes to send HTML mail, which
the GCC lists reject.)

On 1 June 2012 05:22, Gabriel Dos Reis wrote:
> Ok.