找不到 libcrypto 库错误 [英] Cannot find libcrypto library error

问题描述

当我试图编译一个 C 代码，它使用 openssl 'crypto' 库函数和命令行 -lcrypto 和 gcc 4.4.3 它给出了一个错误

When i am trying to compile a C code which uses openssl 'crypto' library functions with comand line -lcrypto with gcc 4.4.3 it gives an error

`@ubu:$ gcc -ggdb aes_m.c -Werror -Wall -I /usr/local/ssl/include/ -lcrypto -o aes
 /usr/bin/ld: cannot find -lcrypto
 collect2: ld returned 1 exit status`

这可能是什么原因??

我已经完成了这个讨论 ld 找不到现有的图书馆但这无济于事.

I have already gone through this discussion ld cannot find an existing library but that does not help.

定位命令结果

$ locate libcrypto
/home/abhi/Downloads/openssl-1.0.1b/libcrypto.a
/home/abhi/Downloads/openssl-1.0.1b/libcrypto.pc
/lib/libcrypto.so.0.9.8
/lib/i486/libcrypto.so.0.9.8
/lib/i586/libcrypto.so.0.9.8
/lib/i686/cmov/libcrypto.so.0.9.8
/usr/lib/libcrypto.so.0.9.8
/usr/lib/vmware-tools/lib32/libcrypto.so.0.9.8
/usr/lib/vmware-tools/lib32/libcrypto.so.0.9.8/libcrypto.so.0.9.8
/usr/lib/vmware-tools/lib64/libcrypto.so.0.9.8
/usr/lib/vmware-tools/lib64/libcrypto.so.0.9.8/libcrypto.so.0.9.8
/usr/local/ssl/lib/libcrypto.a
/usr/local/ssl/lib/pkgconfig/libcrypto.pc

有人可以帮忙解决这个问题或指出我做的任何错误

Can someone please help on this or point out any mistake i am doing

@ Daniel Roethlisberger 尝试使用 -L 标志，但导致这些错误

@ Daniel Roethlisberger tried using the -L flag but that resulted in these errors

gcc -ggdb aes_m.c -Werror -Wall -I /usr/local/ssl/include/ -L /usr/local/ssl/lib -lcrypto -o aes
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_globallookup':
dso_dlfcn.c:(.text+0x2d): undefined reference to `dlopen'
dso_dlfcn.c:(.text+0x43): undefined reference to `dlsym'
dso_dlfcn.c:(.text+0x4d): undefined reference to `dlclose'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_pathbyaddr':
dso_dlfcn.c:(.text+0x8f): undefined reference to `dladdr'
dso_dlfcn.c:(.text+0xe9): undefined reference to `dlerror'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_func':
dso_dlfcn.c:(.text+0x4b1): undefined reference to `dlsym'
dso_dlfcn.c:(.text+0x590): undefined reference to `dlerror'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_var':
dso_dlfcn.c:(.text+0x611): undefined reference to `dlsym'
dso_dlfcn.c:(.text+0x6f0): undefined reference to `dlerror'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_unload':
dso_dlfcn.c:(.text+0x755): undefined reference to `dlclose'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_load':
dso_dlfcn.c:(.text+0x837): undefined reference to `dlopen'
dso_dlfcn.c:(.text+0x8ae): undefined reference to `dlclose'
dso_dlfcn.c:(.text+0x8f5): undefined reference to `dlerror'
collect2: ld returned 1 exit status

非常感谢

推荐答案

将 -L/usr/local/ssl/lib/ 添加到 GCC 命令行中，在 -lcrypto<之前/代码>.由于您是针对 /usr/local/ssl 下的 OpenSSL 标头构建的，因此您还需要链接到相同前缀下的实际库(即使您似乎只在那里安装了静态库，这可能是也可能不是您的意图；您可能需要正确地重新安装从源代码构建的 OpenSSL).

Add -L /usr/local/ssl/lib/ into the GCC command line, before the -lcrypto. Since you are building against the OpenSSL headers under /usr/local/ssl, you also need to link against the actual library under the same prefix (even though you only appear to have a static one installed there, that may or may not be your intention; you may need to properly reinstall your OpenSSL built from source).

(edit) 要修复链接器找不到 dlopen() 和朋友的问题，请将 -ldl 添加到 GCC 命令行中.-ldl 告诉链接器也链接到 libdl.so，这是包含 dlopen(), dlsym(), 的共享库>dlclose() 等；这些函数由 OpenSSL 在内部使用，因此，当使用 -lcrypto(在 Linux 上)时，-ldl 是一个间接依赖项.因为您要链接到 libcrypto 的静态版本，所以您需要显式链接所有间接依赖项.

(edit) To fix the dlopen() and friends not being found by the linker, add -ldl into the GCC command line. -ldl tells the linker to also link against libdl.so, which is the shared library containing dlopen(), dlsym(), dlclose() etc.; these functions are used by OpenSSL internally and thus, -ldl is an indirect dependency when using -lcrypto (on Linux). Because you are linking to a static version of libcrypto, you need to explicitly link against all indirect dependencies.

如果您不熟悉链接到正确的库，我建议您使用从操作系统包管理器安装的 OpenSSL；它可能会为您省去一些麻烦.

If you are not familiar with linking to the proper libraries, I'd suggest you use OpenSSL as installed from your Operating System package manager; it might save you some trouble.

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