C++程序调用 C 函数 在 g++ 链接期间获取未定义的引用

我有一个简单的C++程序，可以调用C函数。 当我链接 2 个对象文件以创建C++可执行文件时，我收到许多"未定义的引用"错误和单个"对 svrport 的多个引用"错误。 我有以下文件 chorusmain.cpp， chorusclient.c， and chorusclient.h. chorusmain.cpp 调用 chorusclient.c 中的函数。 chorusclient.c非常大，我在2年前写了它。 我现在需要在C++应用程序中使用这些函数，并且不想重新编写C++并重新调试代码。 我将chorusclient.c重构为一组可调用的函数。 为简单起见，我将代码简化为仅包含重要组件。

合唱客户

#include <...>
#include "chorusclient.h"
int my_C_Function()
{
...
}

合唱团

#ifdef __cplusplus
extern "C" {
#endif
int my_C_Function();
#ifdef __cplusplus
}
#endif

合唱.cpp

#include <...>
#include "chorusclient.h"
int main(int argc, char *arvg[])
{
...
my_C_Function();
...
}

这是 gcc/g++ 构建和链接命令，

gcc -c -o chorusclient.o chorusclient.c -I/usr/include/json-c - 
I/usr/include/openssl -I/usr/include -I. -I. -lssl -lcrypto -ljson-c
g++ -c -o chorusmain.o chorusmain.cpp -I/usr/share/qt4/mkspecs/linux-g++ -I. - 
I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 - 
I/usr/include -I. -I. -lQtGui -lQtCore -lpthread
g++ -o ChorusMain chorusclient.o chorusmain.o

我在前 2 个 gcc/g++ 版本中没有收到任何错误。 在 g++ 链接期间，我收到以下未定义的引用错误，

debian@beaglebone:~/Projects/CloudClient$ ls
chorusclient.c  chorusclient.h  chorusclient.o  chorusmain.cpp  chorusmain.o
debian@beaglebone:~/Projects/CloudClient$ g++ -o ChorusMain chorusmain.o chorusclient.o
chorusclient.o:(.data+0x0): multiple definition of `svrport'
chorusmain.o:(.data+0x0): first defined here
chorusclient.o: In function `chorusServices':
chorusclient.c:(.text+0x408): undefined reference to `OPENSSL_init_crypto'
chorusclient.c:(.text+0x416): undefined reference to `OPENSSL_init_crypto'
chorusclient.c:(.text+0x41c): undefined reference to `OPENSSL_config'
chorusclient.o: In function `httpSend':
chorusclient.c:(.text+0x1c2c): undefined reference to `OPENSSL_init_ssl'
chorusclient.c:(.text+0x1c3a): undefined reference to `OPENSSL_init_ssl'
chorusclient.c:(.text+0x1c4c): undefined reference to `OPENSSL_init_ssl'
chorusclient.c:(.text+0x1c50): undefined reference to `TLSv1_2_client_method'
chorusclient.c:(.text+0x1c58): undefined reference to `SSL_CTX_new'
chorusclient.c:(.text+0x1c62): undefined reference to `SSL_CTX_set_options'
chorusclient.c:(.text+0x1c7e): undefined reference to `ERR_print_errors_fp'
chorusclient.c:(.text+0x1ca0): undefined reference to `SSL_new'
chorusclient.c:(.text+0x1caa): undefined reference to `SSL_set_fd'
chorusclient.c:(.text+0x1cb0): undefined reference to `SSL_connect'
chorusclient.c:(.text+0x1ce4): undefined reference to `SSL_get_peer_certificate'
chorusclient.c:(.text+0x1cec): undefined reference to `X509_get_subject_name'
chorusclient.c:(.text+0x1cfa): undefined reference to `X509_NAME_oneline'
chorusclient.c:(.text+0x1d1a): undefined reference to `X509_get_issuer_name'
chorusclient.c:(.text+0x1d28): undefined reference to `X509_NAME_oneline'
chorusclient.c:(.text+0x1d3e): undefined reference to `X509_free'
chorusclient.c:(.text+0x1d4a): undefined reference to `SSL_get_current_cipher'
chorusclient.c:(.text+0x1d52): undefined reference to `SSL_CIPHER_get_name'
chorusclient.c:(.text+0x1d80): undefined reference to `SSL_write'
chorusclient.c:(.text+0x1d90): undefined reference to `SSL_read'
chorusclient.c:(.text+0x1df2): undefined reference to `SSL_read'
chorusclient.c:(.text+0x1e8e): undefined reference to `SSL_free'
chorusclient.c:(.text+0x1e9a): undefined reference to `SSL_CTX_free'
chorusclient.o: In function `jsonBatteryData':
chorusclient.c:(.text+0x21a8): undefined reference to `json_object_new_object'
chorusclient.c:(.text+0x21b2): undefined reference to `json_object_new_string'
chorusclient.c:(.text+0x21be): undefined reference to `json_object_new_string'
chorusclient.c:(.text+0x21ca): undefined reference to `json_object_new_string'
chorusclient.c:(.text+0x21d8): undefined reference to `json_object_new_double'
chorusclient.c:(.text+0x21e6): undefined reference to `json_object_new_double'
chorusclient.c:(.text+0x21f4): undefined reference to `json_object_new_double'
chorusclient.c:(.text+0x2202): undefined reference to `json_object_new_double'
chorusclient.c:(.text+0x2210): undefined reference to `json_object_new_double'
chorusclient.c:(.text+0x2220): undefined reference to `json_object_object_add'
chorusclient.c:(.text+0x222e): undefined reference to `json_object_object_add'
chorusclient.c:(.text+0x223c): undefined reference to `json_object_object_add'
chorusclient.c:(.text+0x224a): undefined reference to `json_object_object_add'
chorusclient.c:(.text+0x2258): undefined reference to `json_object_object_add'
chorusclient.o:chorusclient.c:(.text+0x2266): more undefined references to `json_object_object_add' follow
chorusclient.o: In function `jsonBatteryData':
chorusclient.c:(.text+0x2292): undefined reference to `json_object_to_json_string'
chorusclient.o: In function `blockencrypt':
chorusclient.c:(.text+0x22de): undefined reference to `EVP_CIPHER_CTX_new'
chorusclient.c:(.text+0x22ee): undefined reference to `EVP_aes_256_cbc'
chorusclient.c:(.text+0x22fe): undefined reference to `EVP_EncryptInit_ex'
chorusclient.c:(.text+0x231a): undefined reference to `EVP_EncryptUpdate'
chorusclient.c:(.text+0x233c): undefined reference to `EVP_EncryptFinal_ex'
chorusclient.c:(.text+0x2354): undefined reference to `EVP_CIPHER_CTX_free'
chorusclient.o: In function `decrypt':
chorusclient.c:(.text+0x2370): undefined reference to `EVP_CIPHER_CTX_new'
chorusclient.c:(.text+0x2380): undefined reference to `EVP_aes_256_cbc'
chorusclient.c:(.text+0x2390): undefined reference to `EVP_DecryptInit_ex'
chorusclient.c:(.text+0x23ac): undefined reference to `EVP_DecryptUpdate'
chorusclient.c:(.text+0x23ce): undefined reference to `EVP_DecryptFinal_ex'
chorusclient.c:(.text+0x23e6): undefined reference to `EVP_CIPHER_CTX_free'
chorusclient.o: In function `handleErrors':
chorusclient.c:(.text+0x2404): undefined reference to `ERR_print_errors_fp'
collect2: error: ld returned 1 exit status
debian@beaglebone:~/Projects/CloudClient$

当我创建一个调用 chorusclient.c 的简单 C 程序并构建一个链接时，我没有收到未定义的引用错误，并且程序可以正常工作。 有什么想法吗？