Question

我遇到的问题是，当g ++尝试链接目标文件时，我收到以下错误：

11:29:13 **** Build of configuration Debug for project daytime ****
make all 
'Building target: daytime'
'Invoking: Cross G++ Linker'
g++  -o "daytime"  ./tcf/services/daytime.o  ./tcf/main/main.o   
./tcf/services/daytime.o: In function `command_get_time_of_day':
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:38: undefined reference to `json_read_string'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:40: undefined reference to `exception'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:43: undefined reference to `exception'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:52: undefined reference to `write_stringz'
makefile:46: recipe for target 'daytime' failed
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:54: undefined reference to `write_stringz'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:56: undefined reference to `write_errno'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:58: undefined reference to `json_write_string'
./tcf/services/daytime.o: In function `ini_daytime_service':
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:70: undefined reference to `add_command_handler'
collect2.exe: error: ld returned 1 exit status
make: *** [daytime] Error 1

我不知道为什么会出现这种情况，例如包含并找到#include <tcf/framework/json.h>。

没有gcc编译相应的*.c文件，导致发生此链接器错误？这有什么问题？

谢谢。

Answer 1

仅包含头文件是不够的;您还必须指定定义这些函数的库。

要使链接器找到所有这些方法/类（json_read_string，write_stringz，exception），您需要引用该库。如果是它们包含在一个名为libjson.so的库中，你应该这样做：

g++ -ljson -o "daytime"  ./tcf/services/daytime.o  ./tcf/main/main.o

（或者将库添加到项目选项中，如果eclipse正在管理你的make文件）。

或者如果它是另一个.o文件，请在编译中包含它（ - ＆gt;或在项目中，如果eclipse正在创建make文件）。

g ++ undefined reference虽然包含了所有文件

1 个答案: