* Daniel P. Berrange (berra...@redhat.com) wrote:
> Developers on 64-bit machines will often try to perform a
> 32-bit build of QEMU by running
>
> ./configure --extra-cflags="-m32"
>
> Unfortunately if PKG_CONFIG_LIBDIR is not set to point to
> the location of the 32-bit pkg-config files, then configure
> will silently pick up the 64-bit pkg-config files and still
> succeed.
Having fallen into this trap, thanks; seems to do the trick on RHEL7.x:
# /root/try/../qemu/configure --prefix=/root/try
--enable-trace-backends=stderr --extra-cflags="-m32" --extra-ldflags="-m32"
ERROR: sizeof(size_t) doesn't match GLIB_SIZEOF_SIZE_T.
You probably need to set PKG_CONFIG_LIBDIR
to point to the right pkg-config files for your
build target
# export PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig
# /root/try/../qemu/configure --prefix=/root/try
--enable-trace-backends=stderr --extra-cflags="-m32" --extra-ldflags="-m32"
Install prefix /root/try
BIOS directory /root/try/share/qemu
....
and the gsize def (
https://developer.gnome.org/glib/stable/glib-Basic-Types.html#gsize )
does say it should always match size_t size.
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
Dave
>
> This causes a problem for glib because it means QEMU will
> be pulling in /usr/lib64/glib-2.0/include/glibconfig.h
> instead of /usr/lib/glib-2.0/include/glibconfig.h
>
> This causes problems because the 'gsize' type (defined as
> 'unsigned long') will no longer be fully compatible with
> the 'size_t' type (defined as 'unsigned int'). Although
> both are the same size, the compiler refuses to allow
> casts from 'unsigned long *' to 'unsigned int *' as they
> are different pointer types. This results in non-obvious
> compiler errors when building QEMU eg
>
> qga/commands-posix.c: In function ‘qmp_guest_set_user_password’:
> qga/commands-posix.c:1912:55: error: passing argument 2 of ‘g_base64_decode’
> from incompatible pointer type [-Werror=incompatible-pointer-types]
> rawpasswddata = (char *)g_base64_decode(password, &rawpasswdlen);
> ^
> In file included from /usr/include/glib-2.0/glib.h:35:0,
> from qga/commands-posix.c:14:
> /usr/include/glib-2.0/glib/gbase64.h:52:9: note: expected ‘gsize * {aka long
> unsigned int *}’ but argument is of type ‘size_t * {aka unsigned int *}’
> guchar *g_base64_decode (const gchar *text,
> ^
> cc1: all warnings being treated as errors
>
> To detect this problem, add a check to configure that
> verifies that GLIB_SIZEOF_SIZE_T matches sizeof(size_t).
> If this fails print a warning suggesting that the dev
> probably needs to set PKG_CONFIG_LIBDIR.
>
> On Fedora x86_64 it passes with any of:
>
> # ./configure
> # PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig ./configure --extra-cflags="-m32"
> # PKG_CONFIG_LIBDIR=/usr/lib64/pkgconfig ./configure --extra-cflags="-m64"
>
> And fails with a mis-match
>
> # PKG_CONFIG_LIBDIR=/usr/lib64/pkgconfig ./configure --extra-cflags="-m32"
> # PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig ./configure --extra-cflags="-m64"
>
> ERROR: sizeof(size_t) doesn't match GLIB_SIZEOF_SIZE_T.
> You probably need to set PKG_CONFIG_LIBDIR
> to point to the right pkg-config files for your
> build target
>
> Signed-off-by: Daniel P. Berrange <berra...@redhat.com>
> ---
> Changed in v2:
>
> - Add 'return 0' to silence compiler warning on some
> platforms about returning without a value
>
> configure | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/configure b/configure
> index f75df4b..c53334f 100755
> --- a/configure
> +++ b/configure
> @@ -2939,6 +2939,27 @@ for i in $glib_modules; do
> fi
> done
>
> +# Sanity check that the current size_t matches the
> +# size that glib thinks it should be. This catches
> +# problems on multi-arch where people try to build
> +# 32-bit QEMU while pointing at 64-bit glib headers
> +cat > $TMPC <<EOF
> +#include <glib.h>
> +#include <unistd.h>
> +
> +int main(void) {
> + G_STATIC_ASSERT(sizeof(size_t) == GLIB_SIZEOF_SIZE_T);
> + return 0;
> +}
> +EOF
> +
> +if ! compile_prog "-Werror $CFLAGS" "$LIBS" ; then
> + error_exit "sizeof(size_t) doesn't match GLIB_SIZEOF_SIZE_T."\
> + "You probably need to set PKG_CONFIG_LIBDIR"\
> + "to point to the right pkg-config files for your"\
> + "build target"
> +fi
> +
> # g_test_trap_subprocess added in 2.38. Used by some tests.
> glib_subprocess=yes
> if ! $pkg_config --atleast-version=2.38 glib-2.0; then
> --
> 2.5.0
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
