我试图建立一个共享库,最终交叉编译一段使用对be32toh和le32toh的引用的代码.如果我构建这段代码并从中创建可执行文件,则不会出错:
include $(CLEAR_VARS)
LOCAL_SRC_FILES:= ubertooth.c ubertooth_helper.c
LOCAL_MODULE := ubertooth
LOCAL_C_INCLUDES += jni/libusb jni/libbtbb
LOCAL_SHARED_LIBRARIES := libc libusb libbtbb
LOCAL_LDLIBS := -L$(SYSROOT)/usr/lib -llog
include $(BUILD_EXECUTABLE)
在这里,它可以成功编译:
Compile thumb : ubertooth <= ubertooth.c
Compile thumb : ubertooth <= ubertooth_helper.c
Executable : ubertooth
Install : ubertooth => libs/armeabi/ubertooth
但是,当我尝试通过仅更改Android.mk中的一行来将其构建为共享库时:
include $(CLEAR_VARS)
...
include $(BUILD_SHARED_LIBRARY)
我现在收到以下错误:
Compile thumb : ubertooth <= ubertooth.c
Compile thumb : ubertooth <= ubertooth_helper.c
SharedLibrary : libubertooth.so
./obj/local/armeabi/objs-debug/ubertooth/ubertooth.o: In function `stream_rx_file':
ubertooth.c:224: undefined reference to `be32toh'
./obj/local/armeabi/objs-debug/ubertooth/ubertooth.o: In function `cb_lap':
ubertooth.c:281: undefined reference to `le32toh'
./obj/local/armeabi/objs-debug/ubertooth/ubertooth.o: In function `cb_hop':
ubertooth.c:417: undefined reference to `le32toh'
./obj/local/armeabi/objs-debug/ubertooth/ubertooth.o: In function `cb_btle':
ubertooth.c:506: undefined reference to `le32toh'
collect2: ld returned 1 exit status
我不明白为什么在构建共享库时会出现此链接错误,而在构建可执行文件时却不会.而且,如果我想构建共享库,如何正确链接到我所缺少的东西?
解决方法:
好吧,显然这些宏在sys / endian.h中的NDK中的命名不同:
__uint64_t htobe64(__uint64_t);
__uint32_t htobe32(__uint32_t);
__uint16_t htobe16(__uint16_t);
__uint64_t betoh64(__uint64_t);
__uint32_t betoh32(__uint32_t);
__uint16_t betoh16(__uint16_t);
__uint64_t htole64(__uint64_t);
__uint32_t htole32(__uint32_t);
__uint16_t htole16(__uint16_t);
__uint64_t letoh64(__uint64_t);
__uint32_t letoh32(__uint32_t);
__uint16_t letoh16(__uint16_t);
所以,我用letoh32和betoh32