编译链接C++库报错

RM     libvsrc.a
AR     libvsrc.a
arm-hisiv300-linux-ar: creating libvsrc.a
a - i2c/i2c.o
a - gpio/gpio.o
a - utility/utility.o
a - it6801/it680x.o
a - it6801/edid.o
a - it6801/it680x_cec.o
a - it6801/Remote.o
a - AvVideoSrc.o
G++    main.o
In file included from ./it6801/Mhlrx.h:14:0,
                 from AvVideoSrcIn.h:8,
                 from main.cpp:7:
./it6801/config.h:40:35: note: #pragma message: defined _IT6801_
#pragma message("defined _IT6801_")
                                   ^
LDFLAGS        -static -lpthread -L./
arm-hisiv300-linux-g++ -static -lpthread -L./ -o test_it6801 libvsrc.a main.o  
main.o: In function `main':
main.cpp:(.text.startup+0x4): undefined reference to `CAvVideoSrc::instance()'
main.cpp:(.text.startup+0x10): undefined reference to `CAvVideoSrc::Init(AvVideoSrcMode_E)'
main.cpp:(.text.startup+0x18): undefined reference to `CAvVideoSrc::start()'
collect2: error: ld returned 1 exit status
make: *** [test_it6801] Error 1

前面编译已经生产libvsrc.a，为什么后面生产程序已经链接了libvsrc.a还是报错（undefined reference to）？