Hi Bryce On 20 February 2015 at 23:26, Bryce Harrington <[email protected]> wrote: > On Tue, Feb 17, 2015 at 03:13:32PM +0000, Emil Velikov wrote: >> Currently we use the wayland-scanner executable as found with >> AC_PATH_PROG, and then check the presence of wayland-scanner.pc >> >> Currently the latter is unused even if AC_PATH_PROG fails to find the >> binary. Rework things to use the pkg-config variable as a fall-back. > > Sorry to have to ask some rather stupid questions, but I want to make > sure I understand the effects of this before landing. > >> Cc: Andrew Oakley <[email protected]> >> Cc: Bill Spitzak <[email protected]> >> Cc: Daniel Stone <[email protected]> >> Signed-off-by: Emil Velikov <[email protected]> >> --- >> configure.ac | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/configure.ac b/configure.ac >> index 1db9f79..b44675f 100644 >> --- a/configure.ac >> +++ b/configure.ac >> @@ -503,11 +503,10 @@ AM_CONDITIONAL(HAVE_LCMS, [test "x$have_lcms" = xyes]) >> >> AC_PATH_PROG([wayland_scanner], [wayland-scanner]) >> if test x$wayland_scanner = x; then >> - AC_MSG_ERROR([wayland-scanner is needed to compile weston]) > > Shouldn't there still be an error message generated if the $PKG_CONFIG > run (below) fails? > The macro has an optional [action-if-not-found]. If it's missing (as below) we will error out by default.
>> + PKG_CHECK_MODULES(WAYLAND_SCANNER, [wayland-scanner]) > > Here's where I think I'm confused. The main purpose of > PKG_CHECK_MODULES as I understand it is to define CFLAGS and LIBS > variables, so this would be e.g. WAYLAND_SCANNER_CFLAGS and > WAYLAND_SCANNER_LIBS. Yet I'm not spotting where either of these are > actually used. We only need the binary, not the library stuff, right? > Is it declaring any other variables or doing other work we need? > Afaik the macro does three things 1 Check for the presence of the required package(s) 2 Sets the relevant _CFLAGS and _LIBS variables. 3 Errors out with a very informative message, when action-if-not-found is not set. Here we're using it for 1 & 3. One can use PKG_CHECK_EXISTS() and then manually add the error message, but that is rather uncommon afaict. Hope that clears things up a bit. -Emil _______________________________________________ wayland-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/wayland-devel
