diff --git a/main/BMP.cc b/main/BMP.cc
index 543cc34..74c1b47 100644
--- a/main/BMP.cc
+++ b/main/BMP.cc
@@ -26,11 +26,12 @@ BMP::~BMP()
 
 bool BMP::open(const char * fileName)
 {
+    size_t bytes_read;
     m_fp = fopen(fileName, "r+");
     if (m_fp != NULL)
     {
 		// read file header
-		fread(&m_header, sizeof(m_header), 1, m_fp);
+		bytes_read = fread(&m_header, sizeof(m_header), 1, m_fp);
 		if (m_header.id[0] != 'B' || m_header.id[1] != 'M')
 		{
             cerr << fileName << " does not appear to be a BMP file." << endl;
@@ -38,7 +39,7 @@ bool BMP::open(const char * fileName)
 			m_fp = NULL;
 		}
 		// read image information
-		fread(&m_info, sizeof(m_info), 1, m_fp);	
+		bytes_read = fread(&m_info, sizeof(m_info), 1, m_fp);	
     }
     return (m_fp != NULL);
 }
@@ -46,6 +47,7 @@ bool BMP::open(const char * fileName)
 bool BMP::create(const char * fileName, int width, int height,
                  unsigned char * data)
 {
+    size_t bytes_written;
     m_fp = fopen(fileName, "w+");
     if (m_fp != NULL)
     {
@@ -76,16 +78,16 @@ bool BMP::create(const char * fileName, int width, int height,
         m_info.num_important_colors = 0;
 
         /* write them to the file */
-        fwrite(&m_header, sizeof(m_header), 1, m_fp);
-        fwrite(&m_info, sizeof(m_info), 1, m_fp);
+        bytes_written = fwrite(&m_header, sizeof(m_header), 1, m_fp);
+        bytes_written = fwrite(&m_info, sizeof(m_info), 1, m_fp);
 
         unsigned int zero = 0;
         unsigned char * data_ptr = data + (3 * width) * (height - 1);
         for (int i = 0; i < height; i++)
         {
-            fwrite(data_ptr, 3 * width, 1, m_fp);
+            bytes_written = fwrite(data_ptr, 3 * width, 1, m_fp);
             if (row_padding)
-                fwrite(&zero, row_padding, 1, m_fp);
+                bytes_written = fwrite(&zero, row_padding, 1, m_fp);
             data_ptr -= 3 * width;
         }
     }
@@ -94,6 +96,7 @@ bool BMP::create(const char * fileName, int width, int height,
 
 void BMP::read(unsigned char * buf)
 {
+    size_t bytes_read;
     if (m_fp != NULL)
     {
         int row_data_bytes = 3 * m_info.width;
@@ -108,7 +111,7 @@ void BMP::read(unsigned char * buf)
         unsigned char * data_ptr = buf + row_data_bytes * (m_info.height - 1);
         for (int i = 0; i < m_info.height; i++)
         {
-            fread(data_ptr, row_data_bytes, 1, m_fp);
+            bytes_read = fread(data_ptr, row_data_bytes, 1, m_fp);
             if (row_padding)
                 fseek(m_fp, row_padding, SEEK_CUR);
             data_ptr -= row_data_bytes;