libs: fix API export/import and 'inconsistent linkage' on MSVC

For each lib we build export its own API in headers when we're building it, otherwise import the API from the headers. This fixes linker warnings on Windows when building with MSVC. The problem was that we had defined all GST_*_API decorators unconditionally to GST_EXPORT. This was intentional and only supposed to be temporary, but caused linker warnings because we tell the linker that we want to export all symbols even those from externall DLLs, and when the linker notices that they were in external DLLS and not present locally it warns. What we need to do when building each library is: export the library's own symbols and import all other symbols. To this end we define e.g. BUILDING_GST_FOO and then we define the GST_FOO_API decorator either to export or to import symbols depending on whether BUILDING_GST_FOO is set or not. That way external users of each library API automatically get the import. While we're at it, add new GST_API_EXPORT in config.h and use that for GST_*_API decorators instead of GST_EXPORT. The right export define depends on the toolchain and whether we're using -fvisibility=hidden or not, so it's better to set it to the right thing directly than hard-coding a compiler whitelist in the public header. We put the export define into config.h instead of passing it via the command line to the compiler because it might contain spaces and brackets and in the autotools scenario we'd have to pass that through multiple layers of plumbing and Makefile/shell escaping and we're just not going to be *that* lucky. The export define is only used if we're compiling our lib, not by external users of the lib headers, so it's not a problem to put it into config.h Also, this means all .c files of libs need to include config.h to get the export marker defined, so fix up a few that didn't include config.h. This commit depends on a common submodule commit that makes gst-glib-gen.mak add an #include "config.h" to generated enum/marshal .c files for the autotools build. https://bugzilla.gnome.org/show_bug.cgi?id=797185
2024-06-02 08:10:41 +00:00 · 2018-04-28 14:50:11 +01:00 · 2018-04-28 14:50:11 +01:00 · dc29bc4e13
parent cfc8d7ec9e
commit dc29bc4e13
49 changed files with 109 additions and 54 deletions
--- a/2
+++ b/2
@ -1 +1 @@
-Subproject commit ed78bee437dcbe22e6eef0031d9a29d157c0461f
+Subproject commit cd1dee06bf07f094677d0cf3eea4a2e8c2636b24
--- a/configure.ac
+++ b/configure.ac
@ -841,7 +841,13 @@ fi
 AC_SUBST(DEPRECATED_CFLAGS)

 VISIBILITY_CFLAGS=""
-AS_COMPILER_FLAG([-fvisibility=hidden], [VISIBILITY_CFLAGS="-fvisibility=hidden"])
+AS_COMPILER_FLAG([-fvisibility=hidden], [
+  VISIBILITY_CFLAGS="-fvisibility=hidden"
+  AC_DEFINE(GST_API_EXPORT, [extern __attribute__ ((visibility ("default")))], [public symbol export define])
+], [
+  VISIBILITY_CFLAGS=""
+  AC_DEFINE(GST_API_EXPORT, [extern], [public symbol export define])
+])
 AC_SUBST(VISIBILITY_CFLAGS)

 VISIBILITY_CXXFLAGS=""
--- a/gst-libs/gst/allocators/Makefile.am
+++ b/gst-libs/gst/allocators/Makefile.am
@ -17,7 +17,7 @@ libgstallocators_@GST_API_VERSION@_la_SOURCES = \
 	gstdmabuf.c 

 libgstallocators_@GST_API_VERSION@_la_LIBADD = $(GST_LIBS) $(LIBM)
-libgstallocators_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS)
+libgstallocators_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS) -DBUILDING_GST_ALLOCATORS
 libgstallocators_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)

 if HAVE_INTROSPECTION
--- a/gst-libs/gst/allocators/allocators-prelude.h
+++ b/gst-libs/gst/allocators/allocators-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_ALLOCATORS_API
-#define GST_ALLOCATORS_API GST_EXPORT
+#ifdef BUILDING_GST_ALLOCATORS
+#define GST_ALLOCATORS_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_ALLOCATORS_API GST_API_IMPORT
 #endif

 #endif /* __GST_ALLOCATORS_PRELUDE_H__ */
--- a/gst-libs/gst/allocators/meson.build
+++ b/gst-libs/gst/allocators/meson.build
@ -10,7 +10,7 @@ install_headers(gst_allocators_headers, subdir : 'gstreamer-1.0/gst/allocators/'
 gst_allocators_sources = [ 'gstdmabuf.c', 'gstfdmemory.c', 'gstphysmemory.c']
 gstallocators = library('gstallocators-@0@'.format(api_version),
  gst_allocators_sources,
-  c_args : gst_plugins_base_args,
+  c_args : gst_plugins_base_args + ['-DBUILDING_GST_ALLOCATORS'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/app/Makefile.am
+++ b/gst-libs/gst/app/Makefile.am
@ -17,7 +17,7 @@ include $(top_srcdir)/common/gst-glib-gen.mak
 libgstapp_@GST_API_VERSION@_la_SOURCES = gstappsrc.c gstappsink.c
 nodist_libgstapp_@GST_API_VERSION@_la_SOURCES = $(BUILT_SOURCES)
 libgstapp_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) \
-	$(GST_BASE_CFLAGS) $(GST_CFLAGS)
+	$(GST_BASE_CFLAGS) $(GST_CFLAGS) -DBUILDING_GST_APP
 libgstapp_@GST_API_VERSION@_la_LIBADD = $(GST_BASE_LIBS)
 libgstapp_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)

--- a/gst-libs/gst/app/app-prelude.h
+++ b/gst-libs/gst/app/app-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_APP_API
-#define GST_APP_API GST_EXPORT
+#ifdef BUILDING_GST_APP
+#define GST_APP_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_APP_API GST_API_IMPORT
 #endif

 #endif /* __GST_APP_PRELUDE_H__ */
--- a/gst-libs/gst/app/meson.build
+++ b/gst-libs/gst/app/meson.build
@ -9,6 +9,7 @@ install_headers(app_headers, subdir : 'gstreamer-1.0/gst/app/')

 app_enums = gnome.mkenums_simple('app-enumtypes',
  sources : app_mkenum_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
  header_prefix : '#include <gst/app/app-prelude.h>',
  decorator : 'GST_APP_API',
  install_header: true,
@ -20,7 +21,7 @@ app_gen_sources = [gstapp_h]

 gstapp = library('gstapp-@0@'.format(api_version),
  app_sources, gstapp_h, gstapp_c,
-  c_args : gst_plugins_base_args,
+  c_args : gst_plugins_base_args + ['-DBUILDING_GST_APP'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/audio/Makefile.am
+++ b/gst-libs/gst/audio/Makefile.am
@ -104,7 +104,7 @@ noinst_HEADERS = \
 	audio-resampler-neon.h

 libgstaudio_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS) \
-		$(ORC_CFLAGS)
+		$(ORC_CFLAGS) -DBUILDING_GST_AUDIO
 libgstaudio_@GST_API_VERSION@_la_LIBADD = \
  $(top_builddir)/gst-libs/gst/tag/libgsttag-@GST_API_VERSION@.la \
  $(GST_BASE_LIBS) $(GST_LIBS) $(LIBM) $(ORC_LIBS)
--- a/gst-libs/gst/audio/audio-prelude.h
+++ b/gst-libs/gst/audio/audio-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_AUDIO_API
-#define GST_AUDIO_API GST_EXPORT
+#ifdef BUILDING_GST_AUDIO
+#define GST_AUDIO_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_AUDIO_API GST_API_IMPORT
 #endif

 #endif /* __GST_AUDIO_PRELUDE_H__ */
--- a/gst-libs/gst/audio/meson.build
+++ b/gst-libs/gst/audio/meson.build
@ -64,6 +64,7 @@ install_headers(audio_headers, subdir : 'gstreamer-1.0/gst/audio/')

 audio_enums = gnome.mkenums_simple('audio-enumtypes',
  sources : audio_mkenum_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
  header_prefix : '#include <gst/audio/audio-prelude.h>',
  decorator : 'GST_AUDIO_API',
  install_header: true,
@ -140,7 +141,7 @@ endif

 gstaudio = library('gstaudio-@0@'.format(api_version),
  audio_src, gstaudio_h, gstaudio_c, orc_c, orc_h,
-  c_args : gst_plugins_base_args + simd_cargs,
+  c_args : gst_plugins_base_args + simd_cargs + ['-DBUILDING_GST_AUDIO'],
  include_directories: [configinc, libsinc],
  link_with : simd_dependencies,
  version : libversion,
--- a/gst-libs/gst/fft/Makefile.am
+++ b/gst-libs/gst/fft/Makefile.am
@ -41,7 +41,7 @@ libgstfft_@GST_API_VERSION@_la_SOURCES = \
 	kiss_fftr_f64.c

 libgstfft_@GST_API_VERSION@_la_LIBADD = $(GST_LIBS) $(LIBM)
-libgstfft_@GST_API_VERSION@_la_CFLAGS =  $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS)
+libgstfft_@GST_API_VERSION@_la_CFLAGS =  $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS) -DBUILDING_GST_FFT
 libgstfft_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)

 EXTRA_DIST = kiss_version
--- a/gst-libs/gst/fft/fft-prelude.h
+++ b/gst-libs/gst/fft/fft-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_FFT_API
-#define GST_FFT_API GST_EXPORT
+#ifdef BUILDING_GST_FFT
+#define GST_FFT_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_FFT_API GST_API_IMPORT
 #endif

 #endif /* __GST_FFT_PRELUDE_H__ */
--- a/gst-libs/gst/fft/meson.build
+++ b/gst-libs/gst/fft/meson.build
@ -27,7 +27,7 @@ install_headers(fft_headers, subdir : 'gstreamer-1.0/gst/fft/')

 gstfft = library('gstfft-@0@'.format(api_version),
  fft_sources,
-  c_args : gst_plugins_base_args,
+  c_args : gst_plugins_base_args + ['-DBUILDING_GST_FFT'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/gl/Makefile.am
+++ b/gst-libs/gst/gl/Makefile.am
@ -155,7 +155,7 @@ configexecincludedir = $(libdir)/gstreamer-@GST_API_VERSION@/include/gst/gl
 nodist_configexecinclude_HEADERS = $(built_sys_header_configure)

 libgstgl_@GST_API_VERSION@_la_CFLAGS = \
-	-DGST_EXPORTS \
+	-DBUILDING_GST_GL \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
 	$(GST_CFLAGS) \
--- a/gst-libs/gst/gl/android/Makefile.am
+++ b/gst-libs/gst/gl/android/Makefile.am
@ -11,6 +11,7 @@ noinst_HEADERS = \
 libgstgl_android_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/gl/cocoa/Makefile.am
+++ b/gst-libs/gst/gl/cocoa/Makefile.am
@ -21,6 +21,7 @@ libgstgl_cocoainclude_HEADERS = \
 libgstgl_cocoa_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/gl/dispmanx/Makefile.am
+++ b/gst-libs/gst/gl/dispmanx/Makefile.am
@ -11,6 +11,7 @@ noinst_HEADERS = \
 libgstgl_dispmanx_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/gl/eagl/Makefile.am
+++ b/gst-libs/gst/gl/eagl/Makefile.am
@ -13,6 +13,7 @@ noinst_HEADERS = \
 libgstgl_eagl_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/gl/egl/Makefile.am
+++ b/gst-libs/gst/gl/egl/Makefile.am
@ -22,6 +22,7 @@ libgstgl_eglinclude_HEADERS = \
 libgstgl_egl_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/gl/gbm/Makefile.am
+++ b/gst-libs/gst/gl/gbm/Makefile.am
@ -15,6 +15,7 @@ noinst_HEADERS = \
 libgstgl_gbm_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/gl/gl-prelude.h
+++ b/gst-libs/gst/gl/gl-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_GL_API
-#define GST_GL_API GST_EXPORT
+#ifdef BUILDING_GST_GL
+#define GST_GL_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_GL_API GST_API_IMPORT
 #endif

 #endif /* __GST_GL_PRELUDE_H__ */
--- a/gst-libs/gst/gl/meson.build
+++ b/gst-libs/gst/gl/meson.build
@ -877,8 +877,8 @@ if build_gstgl

  gstgl = library('gstgl-' + api_version,
    gl_sources,
-    c_args : gst_plugins_base_args + gl_cpp_args,
-    objc_args : gst_plugins_base_args + gl_cpp_args + gl_objc_args,
+    c_args : gst_plugins_base_args + gl_cpp_args + ['-DBUILDING_GST_GL'],
+    objc_args : gst_plugins_base_args + gl_cpp_args + gl_objc_args + ['-DBUILDING_GST_GL'],
    include_directories : [configinc, libsinc, gl_includes],
    version : libversion,
    soversion : soversion,
--- a/gst-libs/gst/gl/viv-fb/Makefile.am
+++ b/gst-libs/gst/gl/viv-fb/Makefile.am
@ -17,6 +17,7 @@ libgstgl_viv_fbinclude_HEADERS = \
 libgstgl_viv_fb_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/gl/wayland/Makefile.am
+++ b/gst-libs/gst/gl/wayland/Makefile.am
@ -18,6 +18,7 @@ libgstgl_waylandinclude_HEADERS = \
 libgstgl_wayland_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/gl/win32/Makefile.am
+++ b/gst-libs/gst/gl/win32/Makefile.am
@ -14,9 +14,9 @@ noinst_HEADERS += gstglcontext_wgl.h
 endif

 libgstgl_win32_la_CFLAGS = \
-	-DGST_EXPORTS \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/gl/x11/Makefile.am
+++ b/gst-libs/gst/gl/x11/Makefile.am
@ -23,6 +23,7 @@ endif
 libgstgl_x11_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
 	-I$(top_builddir)/gst-libs \
+	-DBUILDING_GST_GL \
 	$(GL_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) \
 	$(GST_BASE_CFLAGS) \
--- a/gst-libs/gst/pbutils/Makefile.am
+++ b/gst-libs/gst/pbutils/Makefile.am
@ -54,7 +54,7 @@ libgstpbutils_@GST_API_VERSION@_la_LIBADD = \
  $(top_builddir)/gst-libs/gst/tag/libgsttag-@GST_API_VERSION@.la \
  $(GST_BASE_LIBS) \
  $(GST_LIBS)
-libgstpbutils_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS)
+libgstpbutils_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS) -DBUILDING_GST_PBUTILS
 libgstpbutils_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)

 BUILT_SOURCES = \
--- a/gst-libs/gst/pbutils/meson.build
+++ b/gst-libs/gst/pbutils/meson.build
@ -40,6 +40,7 @@ pbutils_mkenum_headers = pbutils_headers

 pbutils_enums = gnome.mkenums_simple('pbutils-enumtypes',
  sources : pbutils_mkenum_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
  header_prefix : '#include <gst/pbutils/pbutils-prelude.h>',
  decorator : 'GST_PBUTILS_API',
  install_header: true,
@ -50,7 +51,7 @@ gstpbutils_h = pbutils_enums[1]
 gstpbutils_deps = [video_dep, audio_dep, tag_dep]
 pbutils = library('gstpbutils-@0@'.format(api_version),
  pbutils_sources, gstpbutils_c, gstpbutils_h,
-  c_args : gst_plugins_base_args,
+  c_args : gst_plugins_base_args + ['-DBUILDING_GST_PBUTILS'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/pbutils/pbutils-prelude.h
+++ b/gst-libs/gst/pbutils/pbutils-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_PBUTILS_API
-#define GST_PBUTILS_API GST_EXPORT
+#ifdef BUILDING_GST_PBUTILS
+#define GST_PBUTILS_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_PBUTILS_API GST_API_IMPORT
 #endif

 #ifndef GST_DISABLE_DEPRECATED
--- a/gst-libs/gst/riff/Makefile.am
+++ b/gst-libs/gst/riff/Makefile.am
@ -18,7 +18,7 @@ libgstriff_@GST_API_VERSION@_la_LIBADD = \
  $(top_builddir)/gst-libs/gst/tag/libgsttag-@GST_API_VERSION@.la \
  $(GST_BASE_LIBS) $(GST_LIBS)

-libgstriff_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS)
+libgstriff_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS) -DBUILDING_GST_RIFF
 libgstriff_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)

 # *** GIR DISABLED for this library ***
--- a/gst-libs/gst/riff/meson.build
+++ b/gst-libs/gst/riff/meson.build
@ -16,7 +16,7 @@ install_headers(riff_headers, subdir : 'gstreamer-1.0/gst/riff/')
 riff_deps = [audio_dep, tag_dep]
 gstriff = library('gstriff-@0@'.format(api_version),
  riff_sources,
-  c_args : gst_plugins_base_args,
+  c_args : gst_plugins_base_args + ['-DBUILDING_GST_RIFF'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/riff/riff-prelude.h
+++ b/gst-libs/gst/riff/riff-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_RIFF_API
-#define GST_RIFF_API GST_EXPORT
+#ifdef BUILDING_GST_RIFF
+#define GST_RIFF_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_RIFF_API GST_API_IMPORT
 #endif

 #endif /* __GST_RIFF_PRELUDE_H__ */
--- a/gst-libs/gst/rtp/Makefile.am
+++ b/gst-libs/gst/rtp/Makefile.am
@ -25,7 +25,7 @@ libgstrtp_@GST_API_VERSION@_la_SOURCES = gstrtpbuffer.c \
 built_sources = gstrtp-enumtypes.c
 built_headers = gstrtp-enumtypes.h

-libgstrtp_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS)
+libgstrtp_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS) -DBUILDING_GST_RTP
 libgstrtp_@GST_API_VERSION@_la_LIBADD = $(GST_BASE_LIBS) $(GST_LIBS)
 libgstrtp_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)

--- a/gst-libs/gst/rtp/meson.build
+++ b/gst-libs/gst/rtp/meson.build
@ -24,6 +24,7 @@ install_headers(rtp_headers, subdir : 'gstreamer-1.0/gst/rtp/')

 rtp_enums = gnome.mkenums_simple('gstrtp-enumtypes',
  sources : rtp_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
  header_prefix : '#include <gst/rtp/rtp-prelude.h>',
  decorator : 'GST_RTP_API',
  install_header: true,
@ -34,7 +35,7 @@ gstrtp_enum_h = rtp_enums[1]
 gstrtp_deps = [audio_dep, gst_base_dep]
 gst_rtp = library('gstrtp-@0@'.format(api_version),
  rtp_sources, gstrtp_enum_c, gstrtp_enum_h,
-  c_args : gst_plugins_base_args,
+  c_args : gst_plugins_base_args + ['-DBUILDING_GST_RTP'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/rtp/rtp-prelude.h
+++ b/gst-libs/gst/rtp/rtp-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_RTP_API
-#define GST_RTP_API GST_EXPORT
+#ifdef BUILDING_GST_RTP
+#define GST_RTP_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_RTP_API GST_API_IMPORT
 #endif

 #endif /* __GST_RTP_PRELUDE_H__ */
--- a/gst-libs/gst/rtsp/Makefile.am
+++ b/gst-libs/gst/rtsp/Makefile.am
@ -34,7 +34,7 @@ nodist_libgstrtspinclude_HEADERS = gstrtsp-enumtypes.h
 #gstrtspextwms.c  
 #rtspextreal.c    

-libgstrtsp_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS) $(GIO_CFLAGS)
+libgstrtsp_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS) $(GIO_CFLAGS) -DBUILDING_GST_RTSP
 libgstrtsp_@GST_API_VERSION@_la_LIBADD = $(GST_BASE_LIBS) $(GST_LIBS) $(GIO_LIBS) $(LIBM)
 libgstrtsp_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS) $(WIN32_LIBS)

--- a/gst-libs/gst/rtsp/meson.build
+++ b/gst-libs/gst/rtsp/meson.build
@ -24,6 +24,7 @@ install_headers(rtsp_headers, subdir : 'gstreamer-1.0/gst/rtsp/')

 rtsp_enums = gnome.mkenums_simple('gstrtsp-enumtypes',
  sources : rtsp_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
  header_prefix : '#include <gst/rtsp/rtsp-prelude.h>',
  decorator : 'GST_RTSP_API',
  install_header: true,
@ -41,7 +42,7 @@ gstrtsp_deps = [gst_base_dep, gst_dep, gio_dep, libm, winsock2]
 gst_rtsp = library('gstrtsp-@0@'.format(api_version),
  rtsp_sources,
  gstrtsp_h, gstrtsp_c,
-  c_args : gst_plugins_base_args,
+  c_args : gst_plugins_base_args + ['-DBUILDING_GST_RTSP'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/rtsp/rtsp-prelude.h
+++ b/gst-libs/gst/rtsp/rtsp-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_RTSP_API
-#define GST_RTSP_API GST_EXPORT
+#ifdef BUILDING_GST_RTSP
+#define GST_RTSP_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_RTSP_API GST_API_IMPORT
 #endif

 #ifndef GST_DISABLE_DEPRECATED
--- a/gst-libs/gst/sdp/Makefile.am
+++ b/gst-libs/gst/sdp/Makefile.am
@ -10,7 +10,7 @@ lib_LTLIBRARIES = libgstsdp-@GST_API_VERSION@.la

 libgstsdp_@GST_API_VERSION@_la_SOURCES = gstsdpmessage.c gstmikey.c

-libgstsdp_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS) $(GIO_CFLAGS)
+libgstsdp_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS) $(GIO_CFLAGS) -DBUILDING_GST_SDP
 libgstsdp_@GST_API_VERSION@_la_LIBADD = $(top_builddir)/gst-libs/gst/rtp/libgstrtp-@GST_API_VERSION@.la $(GST_LIBS) $(GIO_LIBS)
 libgstsdp_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)

--- a/gst-libs/gst/sdp/meson.build
+++ b/gst-libs/gst/sdp/meson.build
@ -11,7 +11,7 @@ rtsp_deps = [rtp_dep, gst_dep, gio_dep]
 gst_sdp_sources = ['gstsdpmessage.c', 'gstmikey.c']
 gstsdp = library('gstsdp-@0@'.format(api_version),
  gst_sdp_sources,
-  c_args : gst_plugins_base_args,
+  c_args : gst_plugins_base_args + ['-DBUILDING_GST_SDP'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/sdp/sdp-prelude.h
+++ b/gst-libs/gst/sdp/sdp-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_SDP_API
-#define GST_SDP_API GST_EXPORT
+#ifdef BUILDING_GST_SDP
+#define GST_SDP_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_SDP_API GST_API_IMPORT
 #endif

 #endif /* __GST_SDP_PRELUDE_H__ */
--- a/gst-libs/gst/tag/Makefile.am
+++ b/gst-libs/gst/tag/Makefile.am
@ -30,7 +30,7 @@ libgsttag_@GST_API_VERSION@_la_SOURCES = \
 nodist_libgsttag_@GST_API_VERSION@_la_SOURCES = $(BUILT_SOURCES)

 libgsttag_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) \
-	$(GST_BASE_CFLAGS) $(GST_CFLAGS) $(ZLIB_CFLAGS) \
+	$(GST_BASE_CFLAGS) $(GST_CFLAGS) $(ZLIB_CFLAGS) -DBUILDING_GST_TAG \
 	-DLICENSE_TRANSLATIONS_PATH=\"$(pkgdatadir)/@GST_API_VERSION@/license-translations.dict\"
 libgsttag_@GST_API_VERSION@_la_LIBADD = $(GST_BASE_LIBS) $(GST_LIBS) $(LIBM) $(ZLIB_LIBS)
 libgsttag_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)
--- a/gst-libs/gst/tag/meson.build
+++ b/gst-libs/gst/tag/meson.build
@ -28,6 +28,7 @@ install_headers(tag_headers, subdir : 'gstreamer-1.0/gst/tag/')

 tag_enums = gnome.mkenums_simple('tag-enumtypes',
  sources : tag_mkenum_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
  header_prefix : '#include <gst/tag/tag-prelude.h>',
  decorator : 'GST_TAG_API',
  install_header: true,
@ -75,7 +76,7 @@ core_conf.set('HAVE_ZLIB', zlib_dep.found())
 tag_deps = [gst_base_dep, libm, zlib_dep]
 gsttag = library('gsttag-@0@'.format(api_version),
  tag_sources, gsttag_h, gsttag_c,
-  c_args : gst_plugins_base_args + gst_tag_args,
+  c_args : gst_plugins_base_args + gst_tag_args + ['-DBUILDING_GST_TAG'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/tag/tag-prelude.h
+++ b/gst-libs/gst/tag/tag-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_TAG_API
-#define GST_TAG_API GST_EXPORT
+#ifdef BUILDING_GST_TAG
+#define GST_TAG_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_TAG_API GST_API_IMPORT
 #endif

 #endif /* __GST_TAG_PRELUDE_H__ */
--- a/gst-libs/gst/video/Makefile.am
+++ b/gst-libs/gst/video/Makefile.am
@ -95,7 +95,7 @@ nodist_libgstvideo_@GST_API_VERSION@include_HEADERS = $(built_headers)
 noinst_HEADERS = gstvideoutilsprivate.h

 libgstvideo_@GST_API_VERSION@_la_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS) \
-					$(ORC_CFLAGS)
+					$(ORC_CFLAGS) -DBUILDING_GST_VIDEO
 libgstvideo_@GST_API_VERSION@_la_LIBADD = $(GST_BASE_LIBS) $(GST_LIBS) $(ORC_LIBS) $(LIBM)
 libgstvideo_@GST_API_VERSION@_la_LDFLAGS = $(GST_LIB_LDFLAGS) $(GST_ALL_LDFLAGS) $(GST_LT_LDFLAGS)

--- a/gst-libs/gst/video/meson.build
+++ b/gst-libs/gst/video/meson.build
@ -89,6 +89,7 @@ video_mkenum_headers = [

 video_enums = gnome.mkenums_simple('video-enumtypes',
  sources : video_mkenum_headers,
+  body_prefix : '#ifdef HAVE_CONFIG_H\n#include "config.h"\n#endif',
  header_prefix : '#include <gst/video/video-prelude.h>',
  decorator : 'GST_VIDEO_API',
  install_header: true,
@ -120,7 +121,7 @@ endif

 gstvideo = library('gstvideo-@0@'.format(api_version),
  video_sources, gstvideo_h, gstvideo_c, orc_c, orc_h,
-  c_args : gst_plugins_base_args,
+  c_args : gst_plugins_base_args + ['-DBUILDING_GST_VIDEO'],
  include_directories: [configinc, libsinc],
  version : libversion,
  soversion : soversion,
--- a/gst-libs/gst/video/video-prelude.h
+++ b/gst-libs/gst/video/video-prelude.h
@ -24,8 +24,10 @@

 #include <gst/gst.h>

-#ifndef GST_VIDEO_API
-#define GST_VIDEO_API GST_EXPORT
+#ifdef BUILDING_GST_VIDEO
+#define GST_VIDEO_API GST_API_EXPORT         /* from config.h */
+#else
+#define GST_VIDEO_API GST_API_IMPORT
 #endif

 #endif /* __GST_VIDEO_PRELUDE_H__ */
--- a/meson.build
+++ b/meson.build
@ -59,11 +59,21 @@ if cc.has_link_argument('-Wl,-Bsymbolic-functions')
  add_project_link_arguments('-Wl,-Bsymbolic-functions', language : 'c')
 endif

+core_conf = configuration_data()
+
 # Symbol visibility
-if cc.has_argument('-fvisibility=hidden')
+if cc.get_id() == 'msvc'
+  export_define = '__declspec(dllexport) extern'
+elif cc.has_argument('-fvisibility=hidden')
  add_project_arguments('-fvisibility=hidden', language: 'c')
+  export_define = 'extern __attribute__ ((visibility ("default")))'
+else
+  export_define = 'extern'
 endif

+# Passing this through the command line would be too messy
+core_conf.set('GST_API_EXPORT', export_define)
+
 # Disable strict aliasing
 if cc.has_argument('-fno-strict-aliasing')
  add_project_arguments('-fno-strict-aliasing', language: 'c')
@ -93,7 +103,6 @@ if glib_checks.disabled() or (glib_checks.auto() and not gst_version_is_dev)
  add_project_arguments('-DG_DISABLE_CHECKS', language: 'c')
 endif

-core_conf = configuration_data()
 check_headers = [
  ['HAVE_DLFCN_H', 'dlfcn.h'],
  ['HAVE_EMMINTRIN_H', 'emmintrin.h'],