libvirt @5.5.0: error: expected ';' before 'virTemporaryReturnPointer'

[kencu (Ken)]

On my current system (10.6.8) libvirt 5.5.0 does not build:

libtool: compile:  /opt/local/bin/clang-mp-5.0 -DHAVE_CONFIG_H -I. -I.. -I../gnulib/lib -I../gnulib/lib -I.. -I../include -I../include -I./util -I./util -DIN_LIBVIRT -Dabs_top_builddir=\"/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_sysutils_libvirt/libvirt/work/libvirt-5.5.0\" -Dabs_top_srcdir=\"/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_sysutils_libvirt/libvirt/work/libvirt-5.5.0\" -I/opt/local/include -std=gnu99 -I/opt/local/include/yajl -I/opt/local/include/libxml2 -fno-common -W -Waddress -Wall -Wattributes -Wbad-function-cast -Wbuiltin-macro-redefined -Wcast-align -Wchar-subscripts -Wcomment -Wcomments -Wcpp -Wdangling-else -Wdate-time -Wdeprecated-declarations -Wdiv-by-zero -Wdouble-promotion -Wduplicate-decl-specifier -Wempty-body -Wendif-labels -Wexpansion-to-defined -Wextra -Wformat-extra-args -Wformat-security -Wformat-y2k -Wformat-zero-length -Wignored-attributes -Wignored-qualifiers -Wimplicit -Wimplicit-function-declaration -Wimplicit-int -Wincompatible-pointer-types -Winit-self -Winline -Wint-conversion -Wint-to-pointer-cast -Winvalid-pch -Wlogical-not-parentheses -Wmain -Wmissing-braces -Wmissing-declarations -Wmissing-field-initializers -Wmissing-include-dirs -Wmissing-prototypes -Wmultichar -Wnarrowing -Wnested-externs -Wnonnull -Wnull-dereference -Wodr -Wold-style-definition -Woverflow -Wparentheses -Wpointer-arith -Wpointer-sign -Wpointer-to-int-cast -Wpragmas -Wreturn-type -Wsequence-point -Wshadow -Wshift-count-negative -Wshift-count-overflow -Wshift-negative-value -Wsizeof-array-argument -Wsizeof-pointer-memaccess -Wstrict-aliasing -Wstrict-prototypes -Wswitch -Wswitch-bool -Wtautological-compare -Wtrigraphs -Wtype-limits -Wuninitialized -Wunknown-pragmas -Wunused -Wunused-function -Wunused-label -Wunused-local-typedefs -Wunused-parameter -Wunused-result -Wunused-value -Wunused-variable -Wvarargs -Wvariadic-macros -Wvolatile-register-var -Wwrite-strings -Wno-missing-field-initializers -Wno-sign-compare -Wswitch-enum -Wno-format-nonliteral -fexceptions -fasynchronous-unwind-tables -Wframe-larger-than=4096 -I/opt/local/include/p11-kit-1 -pipe -Os -std=c99 -arch x86_64 -MT util/libvirt_util_la-virhostdev.lo -MD -MP -MF util/.deps/libvirt_util_la-virhostdev.Tpo -c util/virhostdev.c  -fno-common -DPIC -o util/.libs/libvirt_util_la-virhostdev.o
util/virhostdev.c:202:5: warning: implicit declaration of function 'typeof' is invalid in C99 [-Wimplicit-function-declaration]
    VIR_RETURN_PTR(hostdevMgr);
    ^
./internal.h:291:9: note: expanded from macro 'VIR_RETURN_PTR'
        typeof(ptr) virTemporaryReturnPointer = (ptr); \
        ^
util/virhostdev.c:202:5: warning: this function declaration is not a prototype [-Wstrict-prototypes]
./internal.h:291:9: note: expanded from macro 'VIR_RETURN_PTR'
        typeof(ptr) virTemporaryReturnPointer = (ptr); \
        ^
util/virhostdev.c:202:5: error: expected ';' after expression
./internal.h:291:21: note: expanded from macro 'VIR_RETURN_PTR'
        typeof(ptr) virTemporaryReturnPointer = (ptr); \
                    ^
util/virhostdev.c:202:5: error: use of undeclared identifier 'virTemporaryReturnPointer'
./internal.h:291:21: note: expanded from macro 'VIR_RETURN_PTR'
        typeof(ptr) virTemporaryReturnPointer = (ptr); \
                    ^
util/virhostdev.c:202:5: error: use of undeclared identifier 'virTemporaryReturnPointer'
./internal.h:293:16: note: expanded from macro 'VIR_RETURN_PTR'
        return virTemporaryReturnPointer; \
               ^
util/virhostdev.c:252:5: error: expected ';' after expression
    VIR_RETURN_PTR(pcidevs);
    ^
./internal.h:291:21: note: expanded from macro 'VIR_RETURN_PTR'
        typeof(ptr) virTemporaryReturnPointer = (ptr); \
                    ^
util/virhostdev.c:252:5: error: use of undeclared identifier 'virTemporaryReturnPointer'
./internal.h:291:21: note: expanded from macro 'VIR_RETURN_PTR'
        typeof(ptr) virTemporaryReturnPointer = (ptr); \
                    ^
util/virhostdev.c:252:5: error: use of undeclared identifier 'virTemporaryReturnPointer'
./internal.h:293:16: note: expanded from macro 'VIR_RETURN_PTR'
        return virTemporaryReturnPointer; \
               ^
2 warnings and 6 errors generated.

I tried building it with clang-5.0, clang-8.0, and gcc6, and all failed similarly. Logs attached.

[kencu (Ken)]

Hmmm. This is <​https://bugzilla.redhat.com/show_bug.cgi?id=1728944> it looks like, and is mentioned in the portfile. Will see if I can figure out how to fix it.

[kencu (Ken)]

this works:

configure.cflags-append -std=gnu99

-std=c11 did not work.

This page <​https://clang.llvm.org/docs/UsersManual.html> suggests clang supports the typeof keyword with any gnu* standard.

The parser recognizes “asm” and “typeof” as keywords in gnu* modes; the variants “__asm__” and “__typeof__” are recognized in all modes.

[ryandesign (Ryan Carsten Schmidt)]

I am aware of this problem, which is why I filed that upstream ticket. The developers declined to fix it because it affects only very old systems.

I had tried -std=c99 which didn't work. I didn't consider that -std=gnu99 might have a different effect. If that fixes it, feel free to commit that.

[kencu (Ken)]

I'm curious how this built successfully on 10.7+ as it was.

Apple's clang must allow the typeof keyword by default, I guess, whereas the llvm clang version does not...

[kencu (Ken)]

The port will not build on Mojave with -std=c99 set in the Portfile:

/bin/sh ../libtool  --tag=CC   --mode=compile /usr/bin/clang -DHAVE_CONFIG_H -I. -I..  -I../gnulib/lib -I../gnulib/lib -I.. -I../include -I../include -I./util -I./util -DIN_LIBVIRT -Dabs_top_builddir="\"/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_sysutils_libvirt/libvirt/work/libvirt-5.5.0\"" -Dabs_top_srcdir="\"/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_sysutils_libvirt/libvirt/work/libvirt-5.5.0\""  -I/opt/local/include -isysroot/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk  -I/opt/local/include/yajl  -I/opt/local/include/libxml2 -fno-common -W -Waddress -Wall -Wattributes -Wbad-function-cast -Wbuiltin-macro-redefined -Wcast-align -Wchar-subscripts -Wcomment -Wcomments -Wcpp -Wdangling-else -Wdate-time -Wdeprecated-declarations -Wdiv-by-zero -Wdouble-promotion -Wduplicate-decl-specifier -Wempty-body -Wendif-labels -Wexpansion-to-defined -Wextra -Wformat-extra-args -Wformat-security -Wformat-y2k -Wformat-zero-length -Wignored-attributes -Wignored-qualifiers -Wimplicit -Wimplicit-function-declaration -Wimplicit-int -Wincompatible-pointer-types -Winit-self -Winline -Wint-conversion -Wint-to-pointer-cast -Winvalid-pch -Wlogical-not-parentheses -Wmain -Wmemset-transposed-args -Wmissing-braces -Wmissing-declarations -Wmissing-field-initializers -Wmissing-include-dirs -Wmissing-prototypes -Wmultichar -Wnarrowing -Wnested-externs -Wnonnull -Wnull-dereference -Wodr -Wold-style-definition -Woverflow -Wparentheses -Wpointer-arith -Wpointer-sign -Wpointer-to-int-cast -Wpragmas -Wreturn-type -Wsequence-point -Wshadow -Wshift-count-negative -Wshift-count-overflow -Wshift-negative-value -Wsizeof-array-argument -Wsizeof-pointer-memaccess -Wstrict-aliasing -Wstrict-prototypes -Wswitch -Wswitch-bool -Wtautological-compare -Wtrigraphs -Wtype-limits -Wuninitialized -Wunknown-pragmas -Wunused -Wunused-function -Wunused-label -Wunused-local-typedefs -Wunused-parameter -Wunused-result -Wunused-value -Wunused-variable -Wvarargs -Wvariadic-macros -Wvolatile-register-var -Wwrite-strings -Wno-sign-compare -Wswitch-enum -Wno-format-nonliteral -fexceptions -fasynchronous-unwind-tables -Wframe-larger-than=4096         -I/opt/local/include/p11-kit-1   -pipe -Os -std=c99 -isysroot/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk -arch x86_64 -MT util/libvirt_util_la-virmodule.lo -MD -MP -MF util/.deps/libvirt_util_la-virmodule.Tpo -c -o util/libvirt_util_la-virmodule.lo `test -f 'util/virmodule.c' || echo './'`util/virmodule.c
util/virhostdev.c:202:5: warning: implicit declaration of function 'typeof' is invalid in C99 [-Wimplicit-function-declaration]
    VIR_RETURN_PTR(hostdevMgr);

If -std=c99 is removed, and no standard is set, then the port builds again on Mojave. So Apple's clang does accept the typeof keyword by default, as opposed to llvm's clang, which does not.

Using -std=gnu99 the port does build with Mojave using the default clang, and also builds with llvm's clang (5 and 8 tested).

So that appears to be a safe fix.

Upstream could consider using __typeof__ instead of typeof and then we would not need to worry about C standards at all.

[ken-cunningham-webuse]

In a933e7a9e7ffe4594529a3f7ec21c08266d60728/macports-ports (master):

libvirt: use gnu99 instead of c99

allows llmv's clang to accept "typeof" keyword
closes: #58726

[ryandesign (Ryan Carsten Schmidt)]

Using -std=gnu99 ​hasn't allowed this port to build on 10.6 any more than -std=c99 did.

[kencu (Ken)]

Did for me, but I build everything on 10.6 with clang-5.0 as per LibcxxOnOlderSystems

The ancient clang that came with 10.6.8 is obviously too old, but the gnu99 is still needed.

[kencu (Ken)]

Anyway, feel free to revert and experiment away if you prefer. There are other possible fixes, as above. As mentioned, I tested clang 5 and 8 and no others.

[kencu (Ken)]

/usr/bin/clang from 10.7 works; /usr/bin/clang from 10.6 does not. New PR in place.

[ryandesign (Ryan Carsten Schmidt)]

Replying to kencu:

/usr/bin/clang from 10.7 works;

I suspect it depends on which version of clang, i.e. which version of Xcode. The last Xcode for 10.7 had clang 425, and ​your PR blacklists all older than that, so that should work. I don't know whether any versions older than that might still work.

[ken-cunningham-webuse]

In 7dbe14fbca99eb1aee26811fd44f8d419b5a6d53/macports-ports (master):

libvirt: tweak blacklisting to fix build on older systems

closes: #58726