LocalFileList.o(.text+0x1a): In function `CLocalFileList::CLocalFileList[not-in-charge](char*)':
/usr/include/sys/stat.h:367: undefined reference to `vtable for CLocalFileList'
LocalFileList.o(.text+0x26):/usr/include/sys/stat.h:367: undefined reference to `vtable for CLocalFileList'
LocalFileList.o(.text+0x32): In function `CLocalFileList::CLocalFileList[not-in-charge](char*)':
/usr/include/c++/3.3.2/bits/basic_string.h:891: undefined reference to `vtable for CLocalFileList'
LocalFileList.o(.text+0x258): In function `CLocalFileList::CLocalFileList[in-charge](char*)':
/home/zd/Projects/ftp/src/LocalFileList.cc:7: undefined reference to `vtable for CLocalFileList'
LocalFileList.o(.text+0x264):/home/zd/Projects/ftp/src/LocalFileList.cc:7: undefined reference to `vtable for CLocalFileList'
LocalFileList.o(.text+0x270):/home/zd/Projects/ftp/src/LocalFileList.cc:7: more undefined references to `vtable for CLocalFileList' follow
collect2: ld returned 1 exit status
make: *** [ftp] Error 1

What does the message mean?
I have define CLocalFileList::CLocalFileList(char*).

CLocalFileList has a father class CFileList.
And the relationship of these class is as follow:
CLocalFileList->CFileList->CCombo->CWidget
->CButton->CWidget
->CCtrlList->CWidget

Did you derive (indirectly) a class from CLocalFileList?
My guess is that the contructor needs to be "virtual".

But how to make a constructor virtual?
And why g++ says "undefined reference to `vtable for CLocalFileList' "?

IIRC (haven't used C++ myself for a while) by putting "virtual" before the decaration (and/or maybe the definition) of the contructor.

The program doesn't know the address of a virtual function until the program is actually running. When the program in run, it looks up the address from a table in memory, the "vtable".

But it's impossible.
If I put "virtual" before the declaration of the constructor,there will be an error when I compile it