c++ - 对`dp_lib_init()`的未定义引用
问题描述
我正在尝试使用Linux TTY Driver Ver 1.0.15.0
这个产品。
我做了所有步骤README_Ubuntu
,在我的项目目录中复制头文件。
但是,它无法编译,抱怨说
/tmp/ccH3NfSt.o: In function `main':
main.cpp:(.text+0x5): undefined reference to `dp_lib_init()'
collect2: error: ld returned 1 exit status
为了编译我的main.cpp
,我用
$ g++ -L/usr/lib -lsdxio main.cpp
// Same result
$ g++ -lsdxio main.cpp
// Same result
$ g++ -L-lsdxio main.cpp
我main.cpp
的是,
#include <iostream>
#include "sdxmng.h"
#include "sdxsio.h"
int main()
{
dp_lib_init();
return 0;
}
我验证了共享库在/usr/lib
-rwxr-xr-x 1 root root 261392 Sep 13 10:53 libsdxio.so
-rwxr-xr-x 1 root root 261392 Sep 13 20:34 libsdxio.so1.0.9.0
-rwxr-xr-x 1 root root 261392 Sep 13 10:53 libsdxio.so.9
一些有用的信息
$ g++ -L/usr/lib -lsdxio main.cpp -Xlinker --verbose
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crt1.o succeeded
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crt1.o
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crti.o succeeded
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crti.o
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/crtbegin.o succeeded
/usr/lib/gcc/x86_64-linux-gnu/5/crtbegin.o
attempt to open /usr/lib/libsdxio.so succeeded
-lsdxio (/usr/lib/libsdxio.so)
attempt to open /tmp/ccKEcpaB.o succeeded
/tmp/ccKEcpaB.o
attempt to open /usr/lib/libstdc++.so failed
attempt to open /usr/lib/libstdc++.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libstdc++.so succeeded
-lstdc++ (/usr/lib/gcc/x86_64-linux-gnu/5/libstdc++.so)
attempt to open /usr/lib/libm.so failed
attempt to open /usr/lib/libm.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libm.so failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libm.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/libm.so succeeded
opened script file /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/libm.so
opened script file /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/libm.so
attempt to open /lib/x86_64-linux-gnu/libm.so.6 succeeded
/lib/x86_64-linux-gnu/libm.so.6
attempt to open /usr/lib/x86_64-linux-gnu/libmvec_nonshared.a succeeded
attempt to open /lib/x86_64-linux-gnu/libmvec.so.1 succeeded
/lib/x86_64-linux-gnu/libmvec.so.1
attempt to open /usr/lib/libgcc_s.so failed
attempt to open /usr/lib/libgcc_s.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libgcc_s.so succeeded
-lgcc_s (/usr/lib/gcc/x86_64-linux-gnu/5/libgcc_s.so)
attempt to open /usr/lib/libgcc.so failed
attempt to open /usr/lib/libgcc.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libgcc.so failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libgcc.a succeeded
attempt to open /usr/lib/libc.so failed
attempt to open /usr/lib/libc.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libc.so failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libc.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/libc.so succeeded
opened script file /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/libc.so
opened script file /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/libc.so
attempt to open /lib/x86_64-linux-gnu/libc.so.6 succeeded
/lib/x86_64-linux-gnu/libc.so.6
attempt to open /usr/lib/x86_64-linux-gnu/libc_nonshared.a succeeded
(/usr/lib/x86_64-linux-gnu/libc_nonshared.a)elf-init.oS
attempt to open /lib/x86_64-linux-gnu/ld-linux-x86-64.so.2 succeeded
/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
attempt to open /usr/lib/libgcc_s.so failed
attempt to open /usr/lib/libgcc_s.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libgcc_s.so succeeded
-lgcc_s (/usr/lib/gcc/x86_64-linux-gnu/5/libgcc_s.so)
attempt to open /usr/lib/libgcc.so failed
attempt to open /usr/lib/libgcc.a failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libgcc.so failed
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/libgcc.a succeeded
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/crtend.o succeeded
/usr/lib/gcc/x86_64-linux-gnu/5/crtend.o
attempt to open /usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crtn.o succeeded
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crtn.o
libm.so.6 needed by /usr/lib/gcc/x86_64-linux-gnu/5/libstdc++.so
found libm.so.6 at /lib/x86_64-linux-gnu/libm.so.6
ld-linux-x86-64.so.2 needed by /usr/lib/gcc/x86_64-linux-gnu/5/libstdc++.so
found ld-linux-x86-64.so.2 at /lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
libgcc_s.so.1 needed by /usr/lib/gcc/x86_64-linux-gnu/5/libstdc++.so
found libgcc_s.so at /usr/lib/gcc/x86_64-linux-gnu/5/libgcc_s.so
/tmp/ccKEcpaB.o: In function `main':
main.cpp:(.text+0x5): undefined reference to `dp_lib_init()'
collect2: error: ld returned 1 exit status
$ ld -lsdxio --verbose
==================================================
attempt to open //usr/local/lib/x86_64-linux-gnu/libsdxio.so failed
attempt to open //usr/local/lib/x86_64-linux-gnu/libsdxio.a failed
attempt to open //lib/x86_64-linux-gnu/libsdxio.so failed
attempt to open //lib/x86_64-linux-gnu/libsdxio.a failed
attempt to open //usr/lib/x86_64-linux-gnu/libsdxio.so failed
attempt to open //usr/lib/x86_64-linux-gnu/libsdxio.a failed
attempt to open //usr/local/lib64/libsdxio.so failed
attempt to open //usr/local/lib64/libsdxio.a failed
attempt to open //lib64/libsdxio.so failed
attempt to open //lib64/libsdxio.a failed
attempt to open //usr/lib64/libsdxio.so failed
attempt to open //usr/lib64/libsdxio.a failed
attempt to open //usr/local/lib/libsdxio.so failed
attempt to open //usr/local/lib/libsdxio.a failed
attempt to open //lib/libsdxio.so failed
attempt to open //lib/libsdxio.a failed
attempt to open //usr/lib/libsdxio.so succeeded
-lsdxio (//usr/lib/libsdxio.so)
libm.so.6 needed by //usr/lib/libsdxio.so
found libm.so.6 at //lib/x86_64-linux-gnu/libm.so.6
libpthread.so.0 needed by //usr/lib/libsdxio.so
found libpthread.so.0 at //lib/x86_64-linux-gnu/libpthread.so.0
libc.so.6 needed by //usr/lib/libsdxio.so
found libc.so.6 at //lib/x86_64-linux-gnu/libc.so.6
ld-linux-x86-64.so.2 needed by //lib/x86_64-linux-gnu/libm.so.6
found ld-linux-x86-64.so.2 at //lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
ld: warning: cannot find entry symbol _start; not setting start address
$ nm libsdxio.so
[...]
0000000000007d19 T dp_lib_free
0000000000007beb T dp_lib_init
0000000000007e21 T dp_mapping
[...]
解决方案
这只是一个猜测,但您似乎包含#include "sdxsio.h"
来自 C++ 源文件的 C 头文件(例如 )。
它通常运行良好,只是您的 C++ 编译器默认情况下会修改函数名称。但二进制文件可能已由 C 编译器编译,默认情况下具有未修改的名称。
因此,即使libsdxio.so
contains dp_lib_init
,您的 C++ 编译器/链接器也会搜索该名称的损坏版本,但无济于事。
解决方案简单而规范(但丑陋):
#ifdef __cplusplus
extern "C" {
#endif
#include "sdxmng.h"
#include "sdxsio.h"
#ifdef __cplusplus
}
#endif
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