Application link error with gcov

Hi,

I'm trying gcov on my Debian VM.
gcov (GCC) 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)
Copyright (C) 2006 Free Software Foundation, Inc.

It work with example program, but I got link error in my application code.

C_FLAGS += -Wall -W -O0 -fprofile-arcs -ftest-coverage

Each class file has the same error:

fileMgr.o: In function `global constructors keyed to 0__ZN7FileMgrC2Ev':
fileMgr.cpp: (.text+0x254da): undefined reference to `__gcov_init'
fileMgr.o: (.data.rel+0x24): undefined reference to `__gcov_merge_add'
backupMgr.o: In function `global constructors keyed to 0__ZN9BackupMgrC2Ev':
backupMgr.cpp: (.text+0x10458): undefined reference to `__gcov_init'
backupMgr.o: (.data.rel+0x24): undefined reference to `__gcov_merge_add'
...
collect2: ld returned 1 exit status
make: *** [fileMgmt] Error 1

Did I missing something?

Thanks!

It should include "-lgcov".