Re: [Libguestfs] [PATCH nbdkit 2/2] tests: Test that public headers are ANSI (ISO C90) compatible.

In commit 3775916120749e935d287f35cb29ff6c586656df (and before that in discussions with Eric) we decided that we should try to allow plugins to be compiled with C compilers other than GCC or Clang (or with very old / peculiar / incompatible versions of those compilers). However until we test this we cannot guarantee that changes to the code will not break this in future, hence this test. Note that GCC or Clang is still required to compile nbdkit itself. --- tests/test-ansi-c-plugin.c | 167 +++++++++++++++++++++++++++++++++++++ tests/Makefile.am | 24 ++++++ tests/test-ansi-c.sh | 39 +++++++++ 3 files changed, 230 insertions(+) diff --git a/tests/test-ansi-c-plugin.c b/tests/test-ansi-c-plugin.c new file mode 100644 index 0000000..8596ca5 --- /dev/null +++ b/tests/test-ansi-c-plugin.c

+ +#include <config.h>

+/* Strictly speaking (and we're compiling with -pedantic, so we _are_

+ * strictly speaking), ANSI C did not allow struct initialization + * using labels. However it was a common extension to C compilers of + * the period. + * + * Therefore we rely here on the order of fields in struct + * nbdkit_plugin. But that's OK because of nbdkit's stable ABI + * guarantee. + * + * If you are really writing an nbdkit plugin which can only use C90 + * then you are advised to find the extension to your compiler which + * allows you to initialize named fields. + */ +static struct nbdkit_plugin plugin = { + 0, 0, 0,

+ "ansic", + 0, + PACKAGE_VERSION, + 0, + ansi_c_load, + 0, + 0, 0, 0, + ansi_c_open, + 0, + ansi_c_get_size, + 0, 0, 0, 0, + ansi_c_pread +}; + +NBDKIT_REGISTER_PLUGIN(plugin)

+++ b/tests/Makefile.am

+# This builds a plugin using an ANSI (ISO C90) compiler to ensure that +# the header file is compatible. The plugin does nothing very +# interesting, it's mainly a compile test. +TESTS += \ + test-ansi-c.sh +# check_LTLIBRARIES won't build a shared library (see automake manual). +# So we have to do this and add a dependency. +noinst_LTLIBRARIES += test-ansi-c-plugin.la +test-ansi-c.sh: test-ansi-c-plugin.la + +test_ansi_c_plugin_la_SOURCES = \ + test-ansi-c-plugin.c \ + $(top_srcdir)/include/nbdkit-plugin.h +test_ansi_c_plugin_la_CPPFLAGS = \ + -std=c90 -pedantic \ + -I$(top_srcdir)/include +test_ansi_c_plugin_la_CFLAGS = \ + $(WARNINGS_CFLAGS) +# For use of the -rpath option, see: +# https://lists.gnu.org/archive/html/libtool/2007-07/msg00067.html +test_ansi_c_plugin_la_LDFLAGS = \ + -module -avoid-version -shared -rpath /nowhere