6 files changed, 35 insertions, 15 deletions
diff --git a/vcl/source/filter/FilterConfigCache.cxx b/vcl/source/filter/FilterConfigCache.cxx
index 369fc3989f04..30f6e4399511 100644
--- a/vcl/source/filter/FilterConfigCache.cxx
+++ b/vcl/source/filter/FilterConfigCache.cxx
@@ -118,7 +118,7 @@ OUString FilterConfigCache::FilterConfigCacheEntry::GetShortName()
 
     @throws It let pass RuntimeExceptions only.
  */
-Reference< XInterface > openConfig(const char* sPackage)
+static Reference< XInterface > openConfig(const char* sPackage)
 {
     Reference< XComponentContext > xContext(
         comphelper::getProcessComponentContext() );
diff --git a/vcl/source/filter/graphicfilter.cxx b/vcl/source/filter/graphicfilter.cxx
index 7aa82f10031b..c2146b962248 100644
--- a/vcl/source/filter/graphicfilter.cxx
+++ b/vcl/source/filter/graphicfilter.cxx
@@ -167,7 +167,7 @@ sal_uInt8* ImplSearchEntry( sal_uInt8* pSource, sal_uInt8 const * pDest, sal_uLo
     return nullptr;
 }
 
-inline OUString ImpGetExtension( const OUString &rPath )
+static inline OUString ImpGetExtension( const OUString &rPath )
 {
     OUString        aExt;
     INetURLObject   aURL( rPath );
diff --git a/vcl/source/filter/graphicfilter2.cxx b/vcl/source/filter/graphicfilter2.cxx
index f9b5ae775c7f..32ad4b51947a 100644
--- a/vcl/source/filter/graphicfilter2.cxx
+++ b/vcl/source/filter/graphicfilter2.cxx
@@ -214,7 +214,7 @@ bool GraphicDescriptor::ImpDetectGIF( SvStream& rStm, bool bExtendedInfo )
 }
 
 // returns the next jpeg marker, a return value of 0 represents an error
-sal_uInt8 ImpDetectJPG_GetNextMarker( SvStream& rStm )
+static sal_uInt8 ImpDetectJPG_GetNextMarker( SvStream& rStm )
 {
     sal_uInt8 nByte;
     do
diff --git a/vcl/source/filter/jpeg/JpegReader.cxx b/vcl/source/filter/jpeg/JpegReader.cxx
index 7b307d7f97cb..1e21b012f0d9 100644
--- a/vcl/source/filter/jpeg/JpegReader.cxx
+++ b/vcl/source/filter/jpeg/JpegReader.cxx
@@ -32,11 +32,13 @@
 
 #define BUFFER_SIZE  4096
 
+extern "C" {
+
 /*
  * Initialize source --- called by jpeg_read_header
  * before any data is actually read.
  */
-extern "C" void init_source (j_decompress_ptr cinfo)
+static void init_source (j_decompress_ptr cinfo)
 {
     SourceManagerStruct * source = reinterpret_cast<SourceManagerStruct *>(cinfo->src);
 
@@ -48,7 +50,9 @@ extern "C" void init_source (j_decompress_ptr cinfo)
     source->no_data_available = FALSE;
 }
 
-long StreamRead( SvStream* pStream, void* pBuffer, long nBufferSize )
+}
+
+static long StreamRead( SvStream* pStream, void* pBuffer, long nBufferSize )
 {
     long nRead = 0;
 
@@ -71,7 +75,9 @@ long StreamRead( SvStream* pStream, void* pBuffer, long nBufferSize )
     return nRead;
 }
 
-extern "C" boolean fill_input_buffer (j_decompress_ptr cinfo)
+extern "C" {
+
+static boolean fill_input_buffer (j_decompress_ptr cinfo)
 {
     SourceManagerStruct * source = reinterpret_cast<SourceManagerStruct *>(cinfo->src);
     size_t nbytes;
@@ -99,7 +105,7 @@ extern "C" boolean fill_input_buffer (j_decompress_ptr cinfo)
     return TRUE;
 }
 
-extern "C" void skip_input_data (j_decompress_ptr cinfo, long numberOfBytes)
+static void skip_input_data (j_decompress_ptr cinfo, long numberOfBytes)
 {
     SourceManagerStruct * source = reinterpret_cast<SourceManagerStruct *>(cinfo->src);
 
@@ -123,11 +129,13 @@ extern "C" void skip_input_data (j_decompress_ptr cinfo, long numberOfBytes)
     }
 }
 
-extern "C" void term_source (j_decompress_ptr)
+static void term_source (j_decompress_ptr)
 {
     /* no work necessary here */
 }
 
+}
+
 void jpeg_svstream_src (j_decompress_ptr cinfo, void* input)
 {
     SourceManagerStruct * source;
diff --git a/vcl/source/filter/jpeg/JpegWriter.cxx b/vcl/source/filter/jpeg/JpegWriter.cxx
index 49e4c6057858..f246c3ea53b3 100644
--- a/vcl/source/filter/jpeg/JpegWriter.cxx
+++ b/vcl/source/filter/jpeg/JpegWriter.cxx
@@ -38,7 +38,9 @@ struct DestinationManagerStruct
     JOCTET * buffer;                  /* start of buffer */
 };
 
-extern "C" void init_destination (j_compress_ptr cinfo)
+extern "C" {
+
+static void init_destination (j_compress_ptr cinfo)
 {
     DestinationManagerStruct * destination = reinterpret_cast<DestinationManagerStruct *>(cinfo->dest);
 
@@ -50,7 +52,7 @@ extern "C" void init_destination (j_compress_ptr cinfo)
     destination->pub.free_in_buffer = BUFFER_SIZE;
 }
 
-extern "C" boolean empty_output_buffer (j_compress_ptr cinfo)
+static boolean empty_output_buffer (j_compress_ptr cinfo)
 {
     DestinationManagerStruct * destination = reinterpret_cast<DestinationManagerStruct *>(cinfo->dest);
 
@@ -65,7 +67,7 @@ extern "C" boolean empty_output_buffer (j_compress_ptr cinfo)
     return TRUE;
 }
 
-extern "C" void term_destination (j_compress_ptr cinfo)
+static void term_destination (j_compress_ptr cinfo)
 {
     DestinationManagerStruct * destination = reinterpret_cast<DestinationManagerStruct *>(cinfo->dest);
     size_t datacount = BUFFER_SIZE - destination->pub.free_in_buffer;
@@ -80,6 +82,8 @@ extern "C" void term_destination (j_compress_ptr cinfo)
     }
 }
 
+}
+
 void jpeg_svstream_dest (j_compress_ptr cinfo, void* output)
 {
     SvStream* stream = static_cast<SvStream*>(output);
diff --git a/vcl/source/filter/jpeg/jpegc.cxx b/vcl/source/filter/jpeg/jpegc.cxx
index cd87781ebd4f..ab56a35c0de7 100644
--- a/vcl/source/filter/jpeg/jpegc.cxx
+++ b/vcl/source/filter/jpeg/jpegc.cxx
@@ -55,7 +55,9 @@ struct ErrorManagerStruct
 #pragma warning(pop)
 #endif
 
-extern "C" void errorExit (j_common_ptr cinfo)
+extern "C" {
+
+static void errorExit (j_common_ptr cinfo)
 {
     char buffer[JMSG_LENGTH_MAX];
     (*cinfo->err->format_message) (cinfo, buffer);
@@ -64,19 +66,23 @@ extern "C" void errorExit (j_common_ptr cinfo)
     longjmp(error->setjmp_buffer, 1);
 }
 
-extern "C" void outputMessage (j_common_ptr cinfo)
+static void outputMessage (j_common_ptr cinfo)
 {
     char buffer[JMSG_LENGTH_MAX];
     (*cinfo->err->format_message) (cinfo, buffer);
     SAL_WARN("vcl.filter", "failure reading JPEG: " << buffer);
 }
 
+}
+
 static int GetWarningLimit()
 {
     return utl::ConfigManager::IsFuzzing() ? 5 : 1000;
 }
 
-extern "C" void emitMessage (j_common_ptr cinfo, int msg_level)
+extern "C" {
+
+static void emitMessage (j_common_ptr cinfo, int msg_level)
 {
     if (msg_level < 0)
     {
@@ -93,6 +99,8 @@ extern "C" void emitMessage (j_common_ptr cinfo, int msg_level)
         cinfo->err->output_message(cinfo);
 }
 
+}
+
 class JpegDecompressOwner
 {
 public:
@@ -139,7 +147,7 @@ struct JpegStuff
     std::vector<sal_uInt8> pCYMKBuffer;
 };
 
-void ReadJPEG(JpegStuff& rContext, JPEGReader* pJPEGReader, void* pInputStream, long* pLines,
+static void ReadJPEG(JpegStuff& rContext, JPEGReader* pJPEGReader, void* pInputStream, long* pLines,
               Size const & previewSize, GraphicFilterImportFlags nImportFlags,
               BitmapScopedWriteAccess* ppAccess)
 {