我有一个头文件ecrt.h，里面包含了一个宏定义#define EC_WRITE_U16 writew(addr,val) 。
按理来说这个头文件是给驱动程序使用的，因为涉及到了内核函数writew。但是我的用户空间也用到了这个头文件ecrt.h，但是没有用到EC_WRITE_U16这个宏定义。
编译过程中出现了如下错误
make all-recursive
make[3]: Entering directory '/home/tsinglin/IGH-1.5.2/ethercat-1.5.2/examples'
Making all in dc_user
make[4]: Entering directory '/home/tsinglin/IGH-1.5.2/ethercat-1.5.2/examples/dc_user'
cd ../.. && automake-1.16 --gnu examples/dc_user/Makefile
cd ../.. && /bin/bash ./config.status examples/dc_user/Makefile depfiles
config.status: creating examples/dc_user/Makefile
config.status: executing depfiles commands
/bin/bash ../../libtool --tag=CC --mode=link gcc -I../../include -Wall -ffunction-sections -fdata-sections -g -O2 -L../../lib/.libs -lethercat -lrt -Wl,--gc-sections -o ec_dc_user_example ec_dc_user_example-main.o
libtool: link: gcc -I../../include -Wall -ffunction-sections -fdata-sections -g -O2 -Wl,--gc-sections -o .libs/ec_dc_user_example ec_dc_user_example-main.o -L../../lib/.libs /home/tsinglin/IGH-1.5.2/ethercat-1.5.2/lib/.libs/libethercat.so -lrt -Wl,-rpath -Wl,/opt/etherlab/lib
/usr/bin/ld: /home/tsinglin/IGH-1.5.2/ethercat-1.5.2/lib/.libs/libethercat.so: undefined reference to `writew'
/usr/bin/ld: /home/tsinglin/IGH-1.5.2/ethercat-1.5.2/lib/.libs/libethercat.so: undefined reference to `writeb'
collect2: error: ld returned 1 exit status
make[4]: *** [Makefile:408: ec_dc_user_example] Error 1
make[4]: Leaving directory '/home/tsinglin/IGH-1.5.2/ethercat-1.5.2/examples/dc_user'
make[3]: *** [Makefile:448: all-recursive] Error 1
make[3]: Leaving directory '/home/tsinglin/IGH-1.5.2/ethercat-1.5.2/examples'
make[2]: *** [Makefile:400: all] Error 2
make[2]: Leaving directory '/home/tsinglin/IGH-1.5.2/ethercat-1.5.2/examples'
make[1]: *** [Makefile:509: all-recursive] Error 1
make[1]: Leaving directory '/home/tsinglin/IGH-1.5.2/ethercat-1.5.2'
make: *** [Makefile:435: all] Error 2
我已经加了编译参数-ffunction-sections -fdata-sections 和-Wl,--gc-sections ，还是过不去，提示undefined reference to `writew'
请问该如何解决呢？
