This new way of writing an options array
static struct program_option const options[] =
{
{ "width", 'w', required_argument },
{ NULL, 'x', no_argument },
{ "help", 'h', no_argument, &show_help, 1 },
{ "version", 'V', no_argument, &show_version, 1 },
};
produces -Wmissing-field-initializers warnings.
-Wmissing-field-initializers is a useful warning in general.
Unfortunately, it cannot be silenced on a per-struct basis.
I see basically three ways out:
* Add a pragma for silencing the warning:
BEGIN_ALLOW_OMITTING_FIELD_INITIALIZERS
static struct program_option const options[] =
{
{ "width", 'w', required_argument },
{ NULL, 'x', no_argument },
{ "help", 'h', no_argument, &show_help, 1 },
{ "version", 'V', no_argument, &show_version, 1 },
};
END_ALLOW_OMITTING_FIELD_INITIALIZERS
* Add initializers in a hidden form:
static struct program_option const options[] =
{
{ "width", 'w', required_argument _NO_ACTION_ },
{ NULL, 'x', no_argument _NO_ACTION_ },
{ "help", 'h', no_argument, &show_help, 1 },
{ "version", 'V', no_argument, &show_version, 1 },
};
* Use a variadic macro that provides the missing initializers:
static struct program_option const options[] =
{
OPTION( "width", 'w', required_argument ),
OPTION( NULL, 'x', no_argument ),
OPTION( "help", 'h', no_argument, &show_help, 1 ),
OPTION( "version", 'V', no_argument, &show_version, 1 ),
};
It's a matter of taste. I prefer the first one.
2025-06-28 Bruno Haible <br...@clisp.org>
options: Avoid -Wmissing-field-initializers warnings.
* lib/options.h (BEGIN_ALLOW_OMITTING_FIELD_INITIALIZERS,
END_ALLOW_OMITTING_FIELD_INITIALIZERS): New macros.
diff --git a/lib/options.h b/lib/options.h
index 6ac33a5ac7..044cc73265 100644
--- a/lib/options.h
+++ b/lib/options.h
@@ -58,6 +58,7 @@
you write
+ BEGIN_ALLOW_OMITTING_FIELD_INITIALIZERS
static struct program_option const options[] =
{
{ "width", 'w', required_argument },
@@ -65,6 +66,7 @@
{ "help", 'h', no_argument, &show_help, 1 },
{ "version", 'V', no_argument, &show_version, 1 },
};
+ END_ALLOW_OMITTING_FIELD_INITIALIZERS
start_options (argc, argv, options, MOVE_OPTIONS_FIRST, 0);
while ((optchar = get_next_option ()) != -1)
@@ -180,6 +182,21 @@ struct program_option
int value;
};
+/* These macros silence '-Wmissing-field-initializers' warnings from GCC and
+ clang in the definition of a 'struct program_option' array.
+ To be placed before and after the declaration of a 'struct program_option'
+ array. */
+#if _GL_GNUC_PREREQ (4, 6) || defined __clang__
+# define BEGIN_ALLOW_OMITTING_FIELD_INITIALIZERS \
+ _Pragma("GCC diagnostic push") \
+ _Pragma("GCC diagnostic ignored \"-Wmissing-field-initializers\"")
+# define END_ALLOW_OMITTING_FIELD_INITIALIZERS \
+ _Pragma("GCC diagnostic pop")
+#else
+# define BEGIN_ALLOW_OMITTING_FIELD_INITIALIZERS
+# define END_ALLOW_OMITTING_FIELD_INITIALIZERS
+#endif
+
/* Handling of non-option arguments. */
enum non_option_handling {
/* Move options before non-option arguments.
