Re: [PATCH for 7.2] Fix broken configure with -Wunused-parameter
On 11/2/22 21:22, Stefan Weil via wrote:
!= "no"; then
cat > $TMPC << EOF
int main(int argc, char *argv[])
{
+(void)argc;
char arr[64], *p = arr, *c = argv[0];
You could use argv[argc - 1] instead.
Paolo
while (*c) {
*p++ = *c++;
Re: [PATCH for 7.2] Fix broken configure with -Wunused-parameter
On 11/3/22 09:58, Daniel P. Berrangé wrote: On Wed, Nov 02, 2022 at 09:22:58PM +0100, Stefan Weil via wrote: The configure script fails because it tries to compile small C programs with a main function which is declared with arguments argc and argv although those arguments are unused. Running `configure -extra-cflags=-Wunused-parameter` triggers the problem. configure for a native build does abort but shows the error in config.log. A cross build configure for Windows with Debian stable aborts with an error. Avoiding unused arguments fixes this. I'm not convinced that we should allow -extra-cflags to influence the configure compile checks at all, as there are likely more cases where arbitrary -W$warn flag will impact the checks, potentially causing configure to silently take the wrong action. Meson cc.compiles/cc.links tests never use -Werror to avoid this (which has a different set of issues, but if you want you can add the argument manually and 0.64 will also add a "werror: true|false" argument). Since the last configure tests will go away in 8.0, I'm fine with just applying this patch in the meanwhile. Paolo
Re: [PATCH for 7.2] Fix broken configure with -Wunused-parameter
Am 03.11.22 um 12:48 schrieb Peter Maydell:
On Wed, 2 Nov 2022 at 20:24, Stefan Weil via wrote:
The configure script fails because it tries to compile small C programs
with a main function which is declared with arguments argc and argv
although those arguments are unused.
Running `configure -extra-cflags=-Wunused-parameter` triggers the problem.
configure for a native build does abort but shows the error in config.log.
A cross build configure for Windows with Debian stable aborts with an
error.
Avoiding unused arguments fixes this.
Signed-off-by: Stefan Weil
---
See https://gitlab.com/qemu-project/qemu/-/issues/1295.
I noticed the problem because I often compile with -Wextra.
Stefan
configure | 7 ---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/configure b/configure
index 4275f5419f..1106c04fea 100755
--- a/configure
+++ b/configure
@@ -1258,6 +1258,7 @@ if test "$stack_protector" != "no"; then
cat > $TMPC << EOF
int main(int argc, char *argv[])
{
+(void)argc;
I'm not a huge fan of this syntax, and it doesn't match the way
we deal with "argument is unused" elsewhere in the codebase
(where we either don't care about it or else use the GCC 'unused'
attribute hidden behind the glib G_GNUC_UNUSED macro).
Any other variant is also fine for me, for example "using" argc by a
"return argc == 0;" instead of "return 0;". Would that be better? If
there is an accepted variant, I can either send a v2 patch, or maybe
such a trivial change can be applied when merging.
I am surprised that this didn't get caught by the check in
do_compiler_werror(), which is supposed to report "this
configure test passed without -Werror but failed with
-Werror, so configure is probably buggy.". That's what's
supposed to catch "your compiler warns on stuff our doesn't
in the test case programs".
If you're building with --disable-werror then configure
should be OK anyway. This is probably a good idea if you want
to build with extra warning arguments in --extra-cflags.
If it doesn't work right even with --disable-werror that's
also something we should investigate.
Cross builds for Windows fail with and without --disable-werror. See
also my bug report https://gitlab.com/qemu-project/qemu/-/issues/1295.
You are right that this is strange and should be investigated,
especially because native builds don't fail like that.
char arr[64], *p = arr, *c = argv[0];
while (*c) {
*p++ = *c++;
@@ -1607,7 +1608,7 @@ fi
if test "$safe_stack" = "yes"; then
cat > $TMPC << EOF
-int main(int argc, char *argv[])
+int main(void)
{
#if ! __has_feature(safe_stack)
#error SafeStack Disabled
@@ -1629,7 +1630,7 @@ EOF
fi
else
cat > $TMPC << EOF
-int main(int argc, char *argv[])
+int main(void)
{
#if defined(__has_feature)
#if __has_feature(safe_stack)
@@ -1675,7 +1676,7 @@ static const int Z = 1;
#define TAUT(X) ((X) == Z)
#define PAREN(X, Y) (X == Y)
#define ID(X) (X)
-int main(int argc, char *argv[])
+int main(void)
{
int x = 0, y = 0;
x = ID(x);
No objection to the cases where we can pass "void", that's
a neater way to write the test anyway.
thanks
-- PMM
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Description: OpenPGP public key
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Re: [PATCH for 7.2] Fix broken configure with -Wunused-parameter
On Wed, 2 Nov 2022 at 20:24, Stefan Weil via wrote:
>
> The configure script fails because it tries to compile small C programs
> with a main function which is declared with arguments argc and argv
> although those arguments are unused.
>
> Running `configure -extra-cflags=-Wunused-parameter` triggers the problem.
> configure for a native build does abort but shows the error in config.log.
> A cross build configure for Windows with Debian stable aborts with an
> error.
>
> Avoiding unused arguments fixes this.
>
> Signed-off-by: Stefan Weil
> ---
>
> See https://gitlab.com/qemu-project/qemu/-/issues/1295.
>
> I noticed the problem because I often compile with -Wextra.
>
> Stefan
>
> configure | 7 ---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/configure b/configure
> index 4275f5419f..1106c04fea 100755
> --- a/configure
> +++ b/configure
> @@ -1258,6 +1258,7 @@ if test "$stack_protector" != "no"; then
>cat > $TMPC << EOF
> int main(int argc, char *argv[])
> {
> +(void)argc;
I'm not a huge fan of this syntax, and it doesn't match the way
we deal with "argument is unused" elsewhere in the codebase
(where we either don't care about it or else use the GCC 'unused'
attribute hidden behind the glib G_GNUC_UNUSED macro).
I am surprised that this didn't get caught by the check in
do_compiler_werror(), which is supposed to report "this
configure test passed without -Werror but failed with
-Werror, so configure is probably buggy.". That's what's
supposed to catch "your compiler warns on stuff our doesn't
in the test case programs".
If you're building with --disable-werror then configure
should be OK anyway. This is probably a good idea if you want
to build with extra warning arguments in --extra-cflags.
If it doesn't work right even with --disable-werror that's
also something we should investigate.
> char arr[64], *p = arr, *c = argv[0];
> while (*c) {
> *p++ = *c++;
> @@ -1607,7 +1608,7 @@ fi
>
> if test "$safe_stack" = "yes"; then
> cat > $TMPC << EOF
> -int main(int argc, char *argv[])
> +int main(void)
> {
> #if ! __has_feature(safe_stack)
> #error SafeStack Disabled
> @@ -1629,7 +1630,7 @@ EOF
>fi
> else
> cat > $TMPC << EOF
> -int main(int argc, char *argv[])
> +int main(void)
> {
> #if defined(__has_feature)
> #if __has_feature(safe_stack)
> @@ -1675,7 +1676,7 @@ static const int Z = 1;
> #define TAUT(X) ((X) == Z)
> #define PAREN(X, Y) (X == Y)
> #define ID(X) (X)
> -int main(int argc, char *argv[])
> +int main(void)
> {
> int x = 0, y = 0;
> x = ID(x);
No objection to the cases where we can pass "void", that's
a neater way to write the test anyway.
thanks
-- PMM
Re: [PATCH for 7.2] Fix broken configure with -Wunused-parameter
Am 03.11.22 um 09:58 schrieb Daniel P. Berrangé: On Wed, Nov 02, 2022 at 09:22:58PM +0100, Stefan Weil via wrote: The configure script fails because it tries to compile small C programs with a main function which is declared with arguments argc and argv although those arguments are unused. Running `configure -extra-cflags=-Wunused-parameter` triggers the problem. configure for a native build does abort but shows the error in config.log. A cross build configure for Windows with Debian stable aborts with an error. Avoiding unused arguments fixes this. I'm not convinced that we should allow -extra-cflags to influence the configure compile checks at all, as there are likely more cases where arbitrary -W$warn flag will impact the checks, potentially causing configure to silently take the wrong action. I partially agree, but configure should fail if invalid -extra-cflags are specified, and the checks must also respect additional include paths given by -extra-cflags of course. And I think that the changes in my patch are an improvement in any case. Stefan OpenPGP_0xE08C21D5677450AD.asc Description: OpenPGP public key OpenPGP_signature Description: OpenPGP digital signature
Re: [PATCH for 7.2] Fix broken configure with -Wunused-parameter
On Wed, Nov 02, 2022 at 09:22:58PM +0100, Stefan Weil via wrote:
> The configure script fails because it tries to compile small C programs
> with a main function which is declared with arguments argc and argv
> although those arguments are unused.
>
> Running `configure -extra-cflags=-Wunused-parameter` triggers the problem.
> configure for a native build does abort but shows the error in config.log.
> A cross build configure for Windows with Debian stable aborts with an
> error.
>
> Avoiding unused arguments fixes this.
I'm not convinced that we should allow -extra-cflags to influence
the configure compile checks at all, as there are likely more cases
where arbitrary -W$warn flag will impact the checks, potentially
causing configure to silently take the wrong action.
>
> Signed-off-by: Stefan Weil
> ---
>
> See https://gitlab.com/qemu-project/qemu/-/issues/1295.
>
> I noticed the problem because I often compile with -Wextra.
>
> Stefan
>
> configure | 7 ---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/configure b/configure
> index 4275f5419f..1106c04fea 100755
> --- a/configure
> +++ b/configure
> @@ -1258,6 +1258,7 @@ if test "$stack_protector" != "no"; then
>cat > $TMPC << EOF
> int main(int argc, char *argv[])
> {
> +(void)argc;
> char arr[64], *p = arr, *c = argv[0];
> while (*c) {
> *p++ = *c++;
> @@ -1607,7 +1608,7 @@ fi
>
> if test "$safe_stack" = "yes"; then
> cat > $TMPC << EOF
> -int main(int argc, char *argv[])
> +int main(void)
> {
> #if ! __has_feature(safe_stack)
> #error SafeStack Disabled
> @@ -1629,7 +1630,7 @@ EOF
>fi
> else
> cat > $TMPC << EOF
> -int main(int argc, char *argv[])
> +int main(void)
> {
> #if defined(__has_feature)
> #if __has_feature(safe_stack)
> @@ -1675,7 +1676,7 @@ static const int Z = 1;
> #define TAUT(X) ((X) == Z)
> #define PAREN(X, Y) (X == Y)
> #define ID(X) (X)
> -int main(int argc, char *argv[])
> +int main(void)
> {
> int x = 0, y = 0;
> x = ID(x);
> --
> 2.30.2
>
>
With regards,
Daniel
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[PATCH for 7.2] Fix broken configure with -Wunused-parameter
The configure script fails because it tries to compile small C programs
with a main function which is declared with arguments argc and argv
although those arguments are unused.
Running `configure -extra-cflags=-Wunused-parameter` triggers the problem.
configure for a native build does abort but shows the error in config.log.
A cross build configure for Windows with Debian stable aborts with an
error.
Avoiding unused arguments fixes this.
Signed-off-by: Stefan Weil
---
See https://gitlab.com/qemu-project/qemu/-/issues/1295.
I noticed the problem because I often compile with -Wextra.
Stefan
configure | 7 ---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/configure b/configure
index 4275f5419f..1106c04fea 100755
--- a/configure
+++ b/configure
@@ -1258,6 +1258,7 @@ if test "$stack_protector" != "no"; then
cat > $TMPC << EOF
int main(int argc, char *argv[])
{
+(void)argc;
char arr[64], *p = arr, *c = argv[0];
while (*c) {
*p++ = *c++;
@@ -1607,7 +1608,7 @@ fi
if test "$safe_stack" = "yes"; then
cat > $TMPC << EOF
-int main(int argc, char *argv[])
+int main(void)
{
#if ! __has_feature(safe_stack)
#error SafeStack Disabled
@@ -1629,7 +1630,7 @@ EOF
fi
else
cat > $TMPC << EOF
-int main(int argc, char *argv[])
+int main(void)
{
#if defined(__has_feature)
#if __has_feature(safe_stack)
@@ -1675,7 +1676,7 @@ static const int Z = 1;
#define TAUT(X) ((X) == Z)
#define PAREN(X, Y) (X == Y)
#define ID(X) (X)
-int main(int argc, char *argv[])
+int main(void)
{
int x = 0, y = 0;
x = ID(x);
--
2.30.2
