Build libsharpyuv as a full installable library.

Headers are installed in a "sharpyuv" subdirectory of the webp dir, e.g. /usr/local/include/webp/sharpyuv/ Remove unnecessary dependency from sharpyuv to webp/types.h Add SHARPYUV_EXTERN so that only symbols meant to be public are exported. Sharpyuv users can use the library with: find_package(WebP) if(TARGET WebP::sharpyuv) # ... use WebP::sharpyuv endif() Change-Id: I602a25521a135a2edc39d6587610484fe6447ec5
2024-12-25 13:18:22 +01:00 · 2022-07-27 17:54:43 +02:00 · 2022-07-27 17:54:43 +02:00 · a3b68c195e
commit a3b68c195e
parent b4994eaa6d
5 changed files with 199 additions and 169 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -218,159 +218,9 @@ configure_file(${CMAKE_CURRENT_LIST_DIR}/cmake/config.h.in
               ${CMAKE_CURRENT_BINARY_DIR}/src/webp/config.h)
 add_definitions(-DHAVE_CONFIG_H)

-# ##############################################################################
-# Build the webpdecoder library.
-
-# Creates a source file with an unused stub function in $CMAKE_BINARY_DIR and
-# adds it to the specified target. Currently used only with Xcode.
-#
-# See also:
-# https://cmake.org/cmake/help/v3.18/command/add_library.html#object-libraries
-# "Some native build systems (such as Xcode) may not like targets that have
-# only object files, so consider adding at least one real source file to any
-# target that references $<TARGET_OBJECTS:objlib>."
-function(libwebp_add_stub_file TARGET)
-  set(stub_source_dir "${CMAKE_BINARY_DIR}")
-  set(stub_source_file
-      "${stub_source_dir}/libwebp_${TARGET}_stub.c")
-  set(stub_source_code
-      "// Generated file. DO NOT EDIT!\n"
-      "// C source file created for target ${TARGET}.\n"
-      "void libwebp_${TARGET}_stub_function(void)\;\n"
-      "void libwebp_${TARGET}_stub_function(void) {}\n")
-  file(WRITE "${stub_source_file}" ${stub_source_code})
-
-  target_sources(${TARGET} PRIVATE ${stub_source_file})
-endfunction()
-
-parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv "WEBP_SHARPYUV_SRCS"
-                  "")
-add_library(sharpyuv OBJECT ${WEBP_SHARPYUV_SRCS})
-target_include_directories(sharpyuv
-                            PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                            ${CMAKE_CURRENT_SOURCE_DIR})
-set_target_properties(
-  sharpyuv
-  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv_csp.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
-
-if(MSVC)
-  # avoid security warnings for e.g., fopen() used in the examples.
-  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
-else()
-  add_definitions(-Wall)
-endif()
-include_directories(${WEBP_DEP_INCLUDE_DIRS})
-add_library(webpdecode OBJECT ${WEBP_DEC_SRCS})
-target_include_directories(webpdecode
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webpdspdecode OBJECT ${WEBP_DSP_COMMON_SRCS} ${WEBP_DSP_DEC_SRCS})
-target_include_directories(webpdspdecode
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webputilsdecode
-            OBJECT
-            ${WEBP_UTILS_COMMON_SRCS}
-            ${WEBP_UTILS_DEC_SRCS})
-target_include_directories(webputilsdecode
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webpdecoder
-            $<TARGET_OBJECTS:webpdecode>
-            $<TARGET_OBJECTS:webpdspdecode>
-            $<TARGET_OBJECTS:webputilsdecode>)
-if(XCODE)
-  libwebp_add_stub_file(webpdecoder)
-endif()
-target_link_libraries(webpdecoder ${WEBP_DEP_LIBRARIES})
-target_include_directories(
-  webpdecoder
-  PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
-  INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
-            $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
-set_target_properties(
-  webpdecoder
-  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
-
-configure_pkg_config("src/libwebpdecoder.pc")
-
-# Build the webp library.
-add_library(webpencode OBJECT ${WEBP_ENC_SRCS})
-target_include_directories(webpencode
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webpdsp
-            OBJECT
-            ${WEBP_DSP_COMMON_SRCS}
-            ${WEBP_DSP_DEC_SRCS}
-            ${WEBP_DSP_ENC_SRCS})
-target_include_directories(webpdsp
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webputils
-            OBJECT
-            ${WEBP_UTILS_COMMON_SRCS}
-            ${WEBP_UTILS_DEC_SRCS}
-            ${WEBP_UTILS_ENC_SRCS})
-target_include_directories(webputils
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webp
-            $<TARGET_OBJECTS:sharpyuv>
-            $<TARGET_OBJECTS:webpdecode>
-            $<TARGET_OBJECTS:webpdsp>
-            $<TARGET_OBJECTS:webpencode>
-            $<TARGET_OBJECTS:webputils>)
-if(XCODE)
-  libwebp_add_stub_file(webp)
-endif()
-target_link_libraries(webp ${WEBP_DEP_LIBRARIES})
-target_include_directories(
-  webp
-  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
-          ${CMAKE_CURRENT_BINARY_DIR}
-  PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>
-         $<INSTALL_INTERFACE:include>)
-set_target_properties(
-  webp
-  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/encode.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
-
-# Make sure the OBJECT libraries are built with position independent code (it is
-# not ON by default).
-set_target_properties(sharpyuv
-                      webpdecode
-                      webpdspdecode
-                      webputilsdecode
-                      webpencode
-                      webpdsp
-                      webputils
-                      PROPERTIES POSITION_INDEPENDENT_CODE ON)
-configure_pkg_config("src/libwebp.pc")
-
-# Build the webp demux library.
-add_library(webpdemux ${WEBP_DEMUX_SRCS})
-target_link_libraries(webpdemux webp)
-target_include_directories(webpdemux
-                           PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
-                                   ${CMAKE_CURRENT_BINARY_DIR}
-                           PUBLIC $<INSTALL_INTERFACE:include>)
-set_target_properties(
-  webpdemux
-  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/demux.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux_types.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
-
-configure_pkg_config("src/demux/libwebpdemux.pc")
-
 # Set the version numbers.
 macro(set_version FILE TARGET_NAME NAME_IN_MAKEFILE)
-  file(READ ${CMAKE_CURRENT_SOURCE_DIR}/src/${FILE} SOURCE_FILE)
+  file(READ ${CMAKE_CURRENT_SOURCE_DIR}/${FILE} SOURCE_FILE)
  string(REGEX MATCH
               "${NAME_IN_MAKEFILE}_la_LDFLAGS[^\n]* -version-info [0-9:]+"
               TMP
@ -420,9 +270,169 @@ macro(set_version FILE TARGET_NAME NAME_IN_MAKEFILE)
                 ${LIBWEBP_MACHO_COMPATIBILITY_VERSION}.${LT_REVISION})
  endif()
 endmacro()
-set_version(Makefile.am webp webp)
-set_version(Makefile.am webpdecoder webpdecoder)
-set_version(demux/Makefile.am webpdemux webpdemux)
+
+# ##############################################################################
+# Build the webpdecoder library.
+
+# Creates a source file with an unused stub function in $CMAKE_BINARY_DIR and
+# adds it to the specified target. Currently used only with Xcode.
+#
+# See also:
+# https://cmake.org/cmake/help/v3.18/command/add_library.html#object-libraries
+# "Some native build systems (such as Xcode) may not like targets that have
+# only object files, so consider adding at least one real source file to any
+# target that references $<TARGET_OBJECTS:objlib>."
+function(libwebp_add_stub_file TARGET)
+  set(stub_source_dir "${CMAKE_BINARY_DIR}")
+  set(stub_source_file
+      "${stub_source_dir}/libwebp_${TARGET}_stub.c")
+  set(stub_source_code
+      "// Generated file. DO NOT EDIT!\n"
+      "// C source file created for target ${TARGET}.\n"
+      "void libwebp_${TARGET}_stub_function(void)\;\n"
+      "void libwebp_${TARGET}_stub_function(void) {}\n")
+  file(WRITE "${stub_source_file}" ${stub_source_code})
+
+  target_sources(${TARGET} PRIVATE ${stub_source_file})
+endfunction()
+
+parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv "WEBP_SHARPYUV_SRCS"
+                  "")
+add_library(sharpyuv ${WEBP_SHARPYUV_SRCS})
+set_version(sharpyuv/Makefile.am sharpyuv sharpyuv)
+target_include_directories(sharpyuv
+                            PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                            ${CMAKE_CURRENT_SOURCE_DIR}
+                            ${CMAKE_CURRENT_SOURCE_DIR}/src)
+set_target_properties(
+  sharpyuv
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv_csp.h")
+install(TARGETS sharpyuv
+        EXPORT ${PROJECT_NAME}Targets
+        PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/webp/sharpyuv
+        INCLUDES
+        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR} ${CMAKE_INSTALL_INCLUDEDIR}/webp
+        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+        RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+
+if(MSVC)
+  # avoid security warnings for e.g., fopen() used in the examples.
+  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
+else()
+  add_definitions(-Wall)
+endif()
+include_directories(${WEBP_DEP_INCLUDE_DIRS})
+add_library(webpdecode OBJECT ${WEBP_DEC_SRCS})
+target_include_directories(webpdecode
+                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                   ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webpdspdecode OBJECT ${WEBP_DSP_COMMON_SRCS} ${WEBP_DSP_DEC_SRCS})
+target_include_directories(webpdspdecode
+                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                   ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webputilsdecode
+            OBJECT
+            ${WEBP_UTILS_COMMON_SRCS}
+            ${WEBP_UTILS_DEC_SRCS})
+target_include_directories(webputilsdecode
+                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                   ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webpdecoder
+            $<TARGET_OBJECTS:webpdecode>
+            $<TARGET_OBJECTS:webpdspdecode>
+            $<TARGET_OBJECTS:webputilsdecode>)
+if(XCODE)
+  libwebp_add_stub_file(webpdecoder)
+endif()
+target_link_libraries(webpdecoder ${WEBP_DEP_LIBRARIES})
+target_include_directories(
+  webpdecoder
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+  INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+            $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+set_target_properties(
+  webpdecoder
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+configure_pkg_config("src/libwebpdecoder.pc")
+
+# Build the webp library.
+add_library(webpencode OBJECT ${WEBP_ENC_SRCS})
+target_include_directories(webpencode
+                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                   ${CMAKE_CURRENT_SOURCE_DIR}
+                                   ${CMAKE_CURRENT_SOURCE_DIR}/src)
+add_library(webpdsp
+            OBJECT
+            ${WEBP_DSP_COMMON_SRCS}
+            ${WEBP_DSP_DEC_SRCS}
+            ${WEBP_DSP_ENC_SRCS})
+target_include_directories(webpdsp
+                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                   ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webputils
+            OBJECT
+            ${WEBP_UTILS_COMMON_SRCS}
+            ${WEBP_UTILS_DEC_SRCS}
+            ${WEBP_UTILS_ENC_SRCS})
+target_include_directories(webputils
+                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                   ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webp
+            $<TARGET_OBJECTS:webpdecode>
+            $<TARGET_OBJECTS:webpdsp>
+            $<TARGET_OBJECTS:webpencode>
+            $<TARGET_OBJECTS:webputils>)
+target_link_libraries(webp sharpyuv)
+if(XCODE)
+  libwebp_add_stub_file(webp)
+endif()
+target_link_libraries(webp ${WEBP_DEP_LIBRARIES})
+target_include_directories(
+  webp
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+          ${CMAKE_CURRENT_BINARY_DIR}
+  PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>
+         $<INSTALL_INTERFACE:include>)
+set_target_properties(
+  webp
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/encode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+# Make sure the OBJECT libraries are built with position independent code (it is
+# not ON by default).
+set_target_properties(webpdecode
+                      webpdspdecode
+                      webputilsdecode
+                      webpencode
+                      webpdsp
+                      webputils
+                      PROPERTIES POSITION_INDEPENDENT_CODE ON)
+configure_pkg_config("src/libwebp.pc")
+
+# Build the webp demux library.
+add_library(webpdemux ${WEBP_DEMUX_SRCS})
+target_link_libraries(webpdemux webp)
+target_include_directories(webpdemux
+                           PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+                                   ${CMAKE_CURRENT_BINARY_DIR}
+                           PUBLIC $<INSTALL_INTERFACE:include>)
+set_target_properties(
+  webpdemux
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/demux.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux_types.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+configure_pkg_config("src/demux/libwebpdemux.pc")
+
+set_version(src/Makefile.am webp webp)
+set_version(src/Makefile.am webpdecoder webpdecoder)
+set_version(src/demux/Makefile.am webpdemux webpdemux)
 file(READ ${CMAKE_CURRENT_SOURCE_DIR}/configure.ac CONFIGURE_FILE)
 string(REGEX MATCH
             "AC_INIT\\([^\n]*\\[[0-9\\.]+\\]"
@ -537,7 +547,7 @@ if(WEBP_BUILD_LIBWEBPMUX)
  target_include_directories(webpmux
                             PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
                                     ${CMAKE_CURRENT_SOURCE_DIR})
-  set_version(mux/Makefile.am webpmux webpmux)
+  set_version(src/mux/Makefile.am webpmux webpmux)
  set_target_properties(webpmux
                        PROPERTIES PUBLIC_HEADER
                                   "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux.h;\
--- a/sharpyuv/Makefile.am
+++ b/sharpyuv/Makefile.am
@ -1,12 +1,16 @@
 AM_CPPFLAGS += -I$(top_builddir) -I$(top_srcdir)
 AM_CPPFLAGS += -I$(top_builddir)/src -I$(top_srcdir)/src
+
+lib_LTLIBRARIES = libsharpyuv.la
+
 noinst_LTLIBRARIES =
-noinst_LTLIBRARIES += libsharpyuv.la
 noinst_LTLIBRARIES += libsharpyuv_sse2.la
 noinst_LTLIBRARIES += libsharpyuv_neon.la

+libsharpyuvinclude_HEADERS =
+libsharpyuvinclude_HEADERS += sharpyuv.h
+libsharpyuvinclude_HEADERS += sharpyuv_csp.h
 noinst_HEADERS =
-noinst_HEADERS += ../src/webp/types.h
 noinst_HEADERS += ../src/dsp/cpu.h

 libsharpyuv_sse2_la_SOURCES =
@ -26,9 +30,8 @@ libsharpyuv_la_SOURCES += sharpyuv_gamma.c sharpyuv_gamma.h
 libsharpyuv_la_SOURCES += sharpyuv.c sharpyuv.h

 libsharpyuv_la_CPPFLAGS = $(AM_CPPFLAGS)
-libsharpyuv_la_LDFLAGS =
+libsharpyuv_la_LDFLAGS = -no-undefined -version-info 0:0:0
 libsharpyuv_la_LIBADD =
 libsharpyuv_la_LIBADD += libsharpyuv_sse2.la
 libsharpyuv_la_LIBADD += libsharpyuv_neon.la
-
-noinst_PROGRAMS =
+libsharpyuvincludedir = $(includedir)/webp/sharpyuv
--- a/sharpyuv/sharpyuv.c
+++ b/sharpyuv/sharpyuv.c
@ -417,7 +417,7 @@ static int DoSharpArgbToYuv(const uint8_t* r_ptr, const uint8_t* g_ptr,
 // Hidden exported init function.
 // By default SharpYuvConvert calls it with NULL. If needed, users can declare
 // it as extern and call it with a VP8CPUInfo function.
-extern void SharpYuvInit(VP8CPUInfo cpu_info_func);
+SHARPYUV_EXTERN void SharpYuvInit(VP8CPUInfo cpu_info_func);
 void SharpYuvInit(VP8CPUInfo cpu_info_func) {
  static volatile VP8CPUInfo sharpyuv_last_cpuinfo_used =
      (VP8CPUInfo)&sharpyuv_last_cpuinfo_used;
--- a/sharpyuv/sharpyuv.h
+++ b/sharpyuv/sharpyuv.h
@ -18,6 +18,20 @@
 extern "C" {
 #endif

+#ifndef SHARPYUV_EXTERN
+#ifdef WEBP_EXTERN
+#define SHARPYUV_EXTERN WEBP_EXTERN
+#else
+// This explicitly marks library functions and allows for changing the
+// signature for e.g., Windows DLL builds.
+#if defined(__GNUC__) && __GNUC__ >= 4
+#define SHARPYUV_EXTERN extern __attribute__((visibility("default")))
+#else
+#define SHARPYUV_EXTERN extern
+#endif /* __GNUC__ >= 4 */
+#endif /* WEBP_EXTERN */
+#endif /* SHARPYUV_EXTERN */
+
 // SharpYUV API version following the convention from semver.org
 #define SHARPYUV_VERSION_MAJOR 0
 #define SHARPYUV_VERSION_MINOR 1
@ -65,11 +79,13 @@ typedef struct {
 //     adjacent pixels on the y, u and v channels. If yuv_bit_depth > 8, they
 //     should be multiples of 2.
 // width, height: width and height of the image in pixels
-int SharpYuvConvert(const void* r_ptr, const void* g_ptr, const void* b_ptr,
-                    int rgb_step, int rgb_stride, int rgb_bit_depth,
-                    void* y_ptr, int y_stride, void* u_ptr, int u_stride,
-                    void* v_ptr, int v_stride, int yuv_bit_depth, int width,
-                    int height, const SharpYuvConversionMatrix* yuv_matrix);
+SHARPYUV_EXTERN int SharpYuvConvert(const void* r_ptr, const void* g_ptr,
+                                    const void* b_ptr, int rgb_step,
+                                    int rgb_stride, int rgb_bit_depth,
+                                    void* y_ptr, int y_stride, void* u_ptr,
+                                    int u_stride, void* v_ptr, int v_stride,
+                                    int yuv_bit_depth, int width, int height,
+                                    const SharpYuvConversionMatrix* yuv_matrix);

 // TODO(b/194336375): Add YUV444 to YUV420 conversion. Maybe also add 422
 // support (it's rarely used in practice, especially for images).
--- a/sharpyuv/sharpyuv_csp.h
+++ b/sharpyuv/sharpyuv_csp.h
@ -35,8 +35,9 @@ typedef struct {
 } SharpYuvColorSpace;

 // Fills in 'matrix' for the given YUVColorSpace.
-void SharpYuvComputeConversionMatrix(const SharpYuvColorSpace* yuv_color_space,
-                                     SharpYuvConversionMatrix* matrix);
+SHARPYUV_EXTERN void SharpYuvComputeConversionMatrix(
+    const SharpYuvColorSpace* yuv_color_space,
+    SharpYuvConversionMatrix* matrix);

 // Enums for precomputed conversion matrices.
 typedef enum {
@ -49,7 +50,7 @@ typedef enum {
 } SharpYuvMatrixType;

 // Returns a pointer to a matrix for one of the predefined colorspaces.
-const SharpYuvConversionMatrix* SharpYuvGetConversionMatrix(
+SHARPYUV_EXTERN const SharpYuvConversionMatrix* SharpYuvGetConversionMatrix(
    SharpYuvMatrixType matrix_type);

 #ifdef __cplusplus