在行的未定义引用`SHA1'

I try to compile a library on linux. this libary uses <openssl/sha.h> library. I have included this library in source file. After that, i use flag -lssl and flag -lcrypto to compile this project. So here is my command :

我尝试在linux上编译一个库。这个库使用库。我已将此库包含在源文件中。之后,我使用flag -lssl和flag -lcrypto来编译这个项目。所以这是我的命令:

gcc -g -Wall -lssl -lcrypto -o bt_client file_a.c file_b.c

gcc -g -Wall -lssl -lcrypto -o bt_client file_a.c file_b.c

But I meet error :

但我遇到了错误:

undefined reference to `SHA1' at line 130

Code at line 130 is :

第130行的代码是:

SHA1((unsigned char *) null_padded_name, 20, (unsigned char *)name_sha1);

Do I miss something ? Please correct me. Thanks :)

我错过了什么吗?请指正。谢谢 :)

3 个解决方案

#1

When you link your application, the linker looks for dependencies in the order you give them on the command line.

链接应用程序时,链接器将按照您在命令行上提供的顺序查找依赖项。

So if you add a library (like -lssl) before the source/object file that depends on that library, the linker will not find any dependencies and ignore the library.

因此,如果在依赖于该库的源/目标文件之前添加库(如-lssl),则链接器将找不到任何依赖项并忽略该库。

This means that you must always put libraries last on the command line.

这意味着您必须始终将库放在命令行上。

#2

Try this:

gcc -g -Wall -o bt_client file_a.c file_b.c -lssl -lcrypto

If you are sure that symbol SHA1 exists in libssl.so or libcrypto.so.

如果您确定libssl.so或libcrypto.so中存在符号SHA1。

#3

You need to provide -lssl and -lcrypto at the end of the command line:

您需要在命令行的末尾提供-lssl和-lcrypto:

gcc -g -Wall -o bt_client file_a.c file_b.c -lssl -lcrypto

#1