问题描述
这里可能有什么问题？我有以下简单的类：
#includelibmnl / libmnl.h
int main （）{
struct mnl_socket * a = mnl_socket_open（12）;
}
运行简单的 gcc compile（ gcc -lmnl main.c ）我得到以下错误：
/tmp/cch3GjuS.o：在函数`main'中：
main.c :(。text + 0xe）：未定义的引用'mnl_socket_open'
collect2：ld返回1退出状态
在共享库上运行nm表明它确实找到了：
aatteka @ aatteka-Dell1：/ tmp $ nm -D /usr/lib/libmnl.so | grep mnl_socket_open
0000000000001810 T mnl_socket_open
这在Ubuntu 12.04上正在发生。安装了 libmnl-dev 和 libmnl0 包。 如果它包含满足在遇到它时已知的未定义参考的符号）。将 What could be wrong here? I have the following simple class: And after running a simple Running nm on the shared library shows that it's actually found: This is happening on Ubuntu 12.04. The libmnl-dev and libmnl0 packages are installed. The Libraries must be listed after the objects that use them (more precisely, a library will be used only if it contains a symbol that satisfies an undefined reference known at the time it is encountered). Move the 这篇关于即使nm指示该符号存在于共享库中，也是未定义的符号引用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ gcc 的 strace 输出表明 ld 正在使用* .so文件：
pre $ [pid 10988] stat（/ usr / lib / gcc / x86_64-linux-gnu / 4.6 / libmnl.so，0x7fff2a39b470）= -1 ENOENT（没有这样的文件或目录）
[pid 10988] open（/ usr / lib / gcc / x86_64-linux-gnu / 4.6 / libmnl.so （/ usr / lib / gcc / x86_64-linux-gnu / 4.6 / libmnl.a，0x7fff2a39b4d0）= -1 ENOENT（没有这样的文件或目录）
[pid 10988] open（/ usr / lib / gcc / x86_64-linux-gnu / 4.6 / libmnl.a，O_RDONLY）= -1 ENOENT （/ usr / lib / gcc / x86_64-linux-gnu / 4.6 /../../../ x86_64-linux-gnu / libmnl.so，0x7fff2a39b470） = -1 ENOENT（没有这样的文件或目录）
[pid 10988] open（/ usr / lib / gcc / x86_64-linux-gnu / 4.6 /../../../ x86_64-linux- gnu / libmnl.so，O_RDONLY）= -1 ENOENT（没有这样的文件或目录）
[pid 10988] stat（/ usr / lib / gcc / x86_64-linux-gnu / 4.6 /../。 ./../x86_64-linux-gn （/ usr / lib / gcc / x86_64-linux-gnu / 4.6 /../。）。 ./../x86_64-linux-gnu/libmnl.a，O_RDONLY）= -1 ENOENT（没有这样的文件或目录）
[pid 10988] stat（/ usr / lib / gcc / x86_64-linux -gnu / 4.6 /../../../../ lib / libmnl.so，{st_mode = S_IFREG | 0644，st_size = 18608，...}）= 0
[pid 10988] open（/ usr / lib / gcc / x86_64-linux-gnu / 4.6 /../../../../ lib / libmnl.so，O_RDONLY）= 7
-lmnl 移到该命令的末尾。#include "libmnl/libmnl.h"
int main() {
struct mnl_socket *a = mnl_socket_open(12);
}
gcc compile (gcc -lmnl main.c) I get the following errors:/tmp/cch3GjuS.o: In function `main':
main.c:(.text+0xe): undefined reference to `mnl_socket_open'
collect2: ld returned 1 exit status
aatteka@aatteka-Dell1:/tmp$ nm -D /usr/lib/libmnl.so | grep mnl_socket_open
0000000000001810 T mnl_socket_open
strace output of gcc indicates that ld is using exactly that *.so file:[pid 10988] stat("/usr/lib/gcc/x86_64-linux-gnu/4.6/libmnl.so", 0x7fff2a39b470) = -1 ENOENT (No such file or directory)
[pid 10988] open("/usr/lib/gcc/x86_64-linux-gnu/4.6/libmnl.so", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 10988] stat("/usr/lib/gcc/x86_64-linux-gnu/4.6/libmnl.a", 0x7fff2a39b4d0) = -1 ENOENT (No such file or directory)
[pid 10988] open("/usr/lib/gcc/x86_64-linux-gnu/4.6/libmnl.a", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 10988] stat("/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/libmnl.so", 0x7fff2a39b470) = -1 ENOENT (No such file or directory)
[pid 10988] open("/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/libmnl.so", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 10988] stat("/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/libmnl.a", 0x7fff2a39b4d0) = -1 ENOENT (No such file or directory)
[pid 10988] open("/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/libmnl.a", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 10988] stat("/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libmnl.so", {st_mode=S_IFREG|0644, st_size=18608, ...}) = 0
[pid 10988] open("/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libmnl.so", O_RDONLY) = 7
-lmnl to the end of the command.