Re: [PATCH] meson: Check for stdarg.h

On a Wednesday in 2020, Daniel P. Berrangé wrote: >On Wed, Sep 02, 2020 at 02:07:54PM +0200, Michal Privoznik wrote: >> As it turns out, one of my previous commits in which I removed >> checking for stdarg.h was too aggressive. Long story short, the >> readline public headers rely on stdarg.h and what is worse, they >> expect us to declare the autotools style of macro (HAVE_STDARG_H) >> if the header file exists. If we don't do it then compiling virsh >> on macos fails. >> >> See 9ea3424a178 for more info. > >Ewww.... > >Deprecated in 2000, removed in 2013, then immediately readded to >"fix" apps which still relied on K&R C with no function prototypes. > >The readline maintainer is more forgiving of ancient application code >than I would be :-) 30 years since arrival of ANSI C is enough time >to update code to use function prototypes, especially if you want to >build against a readline library released in 2020, as opposed to the >old version released years ago. > >> >> Fixes: 85808b73846f93d656b4c81b6ebddd2dc3881bf6 >> Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; >> --- >> meson.build | 8 ++++++-- >> 1 file changed, 6 insertions(+), 2 deletions(-) >> >> diff --git a/meson.build b/meson.build >> index 1aad385ad1..98f7545495 100644 >> --- a/meson.build >> +++ b/meson.build >> @@ -1333,8 +1333,12 @@ if readline_dep.found() >> endif >> endif >> >> - # We need this to avoid compilation issues with modern compilers. >> - # See 9ea3424a178 for a more detailed explanation >> + # We need both of these hacks to avoid compilation issues with modern >> + # compilers. See 9ea3424a178 for a more detailed explanation. >> + if cc.has_header('stdarg.h') >> + conf.set('HAVE_STDARG_H', 1) >> + endif > >Do we have any platforms which lack stdarg.h ? eg can be just add >"#define HAVE_STDARG_H 1" unconditionally in the virsh code before >it includes the readline headers ? > It's part of the C99 standard: https://pubs.opengroup.org/onlinepubs/009695399/basedefs/stdarg.h.html (but I'm still confused why this builds on other platforms even though HAVE_STDARG_H is not defined anywhere) Jano