exception for debug

src/FqBaseBackend.cpp

@@ -137,7 +137,11 @@ int FqBaseBackend::getRead(const unsigned long& offset, char * fq_record) {
     if (i_f_desc==-1) throw std::runtime_error("No open file currently associated to this backend");
 
     int res=lseek(i_f_desc,offset,SEEK_SET);
-    if (res==-1) err(errno,"fseek problem when trying to retrieve dna string.");
+    if (res==-1) {
+        // err(errno,"fseek problem when trying to retrieve dna string.");
+        // add exception for debug
+        throw errno;
+    }
     nread=read(i_f_desc,fq_record,MAX_FQ_RECORD_LENGTH);
     nb_lines=0;
     i=1;