diff --git a/tjbench.c b/tjbench.c
index b09cdaaf..ff09cb77 100644
--- a/tjbench.c
+++ b/tjbench.c
@@ -273,7 +273,7 @@ int decomp(unsigned char *srcbuf, unsigned char **jpegbuf,
 }
 
 
-void fullTest(unsigned char *srcbuf, int w, int h, int subsamp, int jpegqual,
+int fullTest(unsigned char *srcbuf, int w, int h, int subsamp, int jpegqual,
 	char *filename)
 {
 	char tempstr[1024], tempstr2[80];
@@ -470,11 +470,11 @@ void fullTest(unsigned char *srcbuf, int w, int h, int subsamp, int jpegqual,
 	if(jpegsize) {free(jpegsize);  jpegsize=NULL;}
 	if(tmpbuf) {free(tmpbuf);  tmpbuf=NULL;}
 	if(handle) {tjDestroy(handle);  handle=NULL;}
-	return;
+	return retval;
 }
 
 
-void decompTest(char *filename)
+int decompTest(char *filename)
 {
 	FILE *file=NULL;  tjhandle handle=NULL;
 	unsigned char **jpegbuf=NULL, *srcbuf=NULL;
@@ -693,7 +693,7 @@ void decompTest(char *filename)
 	if(srcbuf) {free(srcbuf);  srcbuf=NULL;}
 	if(t) {free(t);  t=NULL;}
 	if(handle) {tjDestroy(handle);  handle=NULL;}
-	return;
+	return retval;
 }
 
 
diff --git a/turbojpeg.c b/turbojpeg.c
index 5aee2e81..c8241329 100644
--- a/turbojpeg.c
+++ b/turbojpeg.c
@@ -122,6 +122,16 @@ static const tjscalingfactor sf[NUMSF]={
 	if(!this) {snprintf(errStr, JMSG_LENGTH_MAX, "Invalid handle");  \
 		return -1;}  \
 	cinfo=&this->cinfo;  dinfo=&this->dinfo;
+#define getcinstance(handle) tjinstance *this=(tjinstance *)handle;  \
+	j_compress_ptr cinfo=NULL;  \
+	if(!this) {snprintf(errStr, JMSG_LENGTH_MAX, "Invalid handle");  \
+		return -1;}  \
+	cinfo=&this->cinfo;
+#define getdinstance(handle) tjinstance *this=(tjinstance *)handle;  \
+	j_decompress_ptr dinfo=NULL;  \
+	if(!this) {snprintf(errStr, JMSG_LENGTH_MAX, "Invalid handle");  \
+		return -1;}  \
+	dinfo=&this->dinfo;
 
 static int getPixelFormat(int pixelSize, int flags)
 {
@@ -605,7 +615,7 @@ DLLEXPORT int DLLCALL tjCompress2(tjhandle handle, unsigned char *srcBuf,
 	unsigned char *rgbBuf=NULL;
 	#endif
 
-	getinstance(handle)
+	getcinstance(handle)
 	if((this->init&COMPRESS)==0)
 		_throw("tjCompress2(): Instance has not been initialized for compression");
 
@@ -710,7 +720,7 @@ DLLEXPORT int DLLCALL tjEncodeYUV3(tjhandle handle, unsigned char *srcBuf,
 	unsigned char *rgbBuf=NULL;
 	#endif
 
-	getinstance(handle);
+	getcinstance(handle);
 
 	for(i=0; i<MAX_COMPONENTS; i++)
 	{
@@ -881,7 +891,7 @@ DLLEXPORT int DLLCALL tjCompressFromYUV(tjhandle handle, unsigned char *srcBuf,
 		tmpbufsize=0, usetmpbuf=0, th[MAX_COMPONENTS];
 	JSAMPLE *_tmpbuf=NULL, *ptr=srcBuf;  JSAMPROW *tmpbuf[MAX_COMPONENTS];
 
-	getinstance(handle)
+	getcinstance(handle)
 
 	for(i=0; i<MAX_COMPONENTS; i++)
 	{
@@ -1045,7 +1055,7 @@ DLLEXPORT int DLLCALL tjDecompressHeader3(tjhandle handle,
 {
 	int retval=0;
 
-	getinstance(handle);
+	getdinstance(handle);
 	if((this->init&DECOMPRESS)==0)
 		_throw("tjDecompressHeader3(): Instance has not been initialized for decompression");
 
@@ -1131,7 +1141,7 @@ DLLEXPORT int DLLCALL tjDecompress2(tjhandle handle, unsigned char *jpegBuf,
 	unsigned char *_dstBuf=NULL;  int _pitch=0;
 	#endif
 
-	getinstance(handle);
+	getdinstance(handle);
 	if((this->init&DECOMPRESS)==0)
 		_throw("tjDecompress2(): Instance has not been initialized for decompression");
 
@@ -1303,7 +1313,7 @@ DLLEXPORT int DLLCALL tjDecodeYUV(tjhandle handle, unsigned char *srcBuf,
 	JMETHOD(int, old_read_markers, (j_decompress_ptr));
 	JMETHOD(void, old_reset_marker_reader, (j_decompress_ptr));
 
-	getinstance(handle);
+	getdinstance(handle);
 
 	for(i=0; i<MAX_COMPONENTS; i++)
 	{
@@ -1452,7 +1462,7 @@ DLLEXPORT int DLLCALL tjDecompressToYUV2(tjhandle handle,
 	JSAMPLE *_tmpbuf=NULL, *ptr=dstBuf;  JSAMPROW *tmpbuf[MAX_COMPONENTS];
 	int dctsize;
 
-	getinstance(handle);
+	getdinstance(handle);
 
 	for(i=0; i<MAX_COMPONENTS; i++)
 	{