ssl - ASN.1结构迭代器仅被声明但未实现

这是我的示例代码：

#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/rsa.h>
#include <openssl/x509.h>

typedef struct key_st {
    X509_ALGOR *algorithm_id;
    RSA *key_material;
} KEY;

DECLARE_ASN1_FUNCTIONS(KEY)

IMPLEMENT_ASN1_FUNCTIONS(KEY)

int main()
{
    return 0;
}

当我编译它时，报告以下错误：

$ gcc -o ssltest ssltest.c -lssl -lcrypto
/tmp/cch0HA77.o: In function `d2i_KEY':
ssltest.c:(.text+0x21): undefined reference to `KEY_it'
/tmp/cch0HA77.o: In function `i2d_KEY':
ssltest.c:(.text+0x48): undefined reference to `KEY_it'
/tmp/cch0HA77.o: In function `KEY_new':
ssltest.c:(.text+0x5e): undefined reference to `KEY_it'
/tmp/cch0HA77.o: In function `KEY_free':
ssltest.c:(.text+0x7a): undefined reference to `KEY_it'
collect2: error: ld returned 1 exit status

检查宏扩展代码后，我发现KEY_it声明为：

extern const ASN1_ITEM KEY_it;

因此，链接器报告未定义的引用。我该如何解决？非常感谢你！

最佳答案

在添加KEY的序列定义后，此问题已解决：

ASN1_SEQUENCE(KEY) = {
    ASN1_SIMPLE(KEY, algorithm_id, X509_ALGOR),
    ASN1_SIMPLE(KEY, key_material, RSAPublicKey)
} ASN1_SEQUENCE_END(KEY)