fixed bug related to output value of lseek that happened only on very large files

src/FqBaseBackend.cpp

@@ -19,7 +19,7 @@
 
 #include "FqBaseBackend.h"
 
-//#define DEBUG
+#define DEBUG
 #ifdef DEBUG
 #include <cassert>
 #include <iostream>
@@ -157,8 +157,8 @@ int FqBaseBackend::getRead(const unsigned long& offset, char * fq_record) {
 #ifdef DEBUG
     cout<<"going to read record at offset: "<<offset<<endl;
 #endif
-    int res=lseek(i_f_desc,offset,SEEK_SET);
-    if (res==-1) {
+    off_t res=lseek(i_f_desc,offset,SEEK_SET);
+    if (res==(off_t)-1) {
 #ifdef DEBUG
         cout<<"Couldn't get read at offset: "<<offset<<endl;
 #endif