Question

我有三个文件，rsa.c，prf.c和rsa-test.c。

我使用gcc -c rsa.c，gcc -c prf.c，gcc -c rsa-test.c来获取.o文件。

编辑：我在rsa-test.c中包含了rsa.c和prf.c。

然后我使用gcc -o test rsa.o prf.o rsa-test.o编译.o文件。

编译时出现以下错误。 o三个文件的文件。

Undefined symbols for architecture x86_64:
  "_EVP_sha512", referenced from:
      randBytes(unsigned char*, unsigned long) in prf.o
  "_HMAC", referenced from:
      randBytes(unsigned char*, unsigned long) in prf.o
  "_SHA512", referenced from:
      setSeed(unsigned char*, unsigned long) in prf.o
  "___gmpz_add_ui", referenced from:
      randBytes(unsigned char*, unsigned long) in prf.o
  "___gmpz_clear", referenced from:
      rsa_shredKey(_RSA_KEY*) in rsa.o
  "___gmpz_export", referenced from:
      zToFile(__sFILE*, __mpz_struct*) in rsa.o
  "___gmpz_import", referenced from:
      zFromFile(__sFILE*, __mpz_struct*) in rsa.o
  "___gmpz_init", referenced from:
      rsa_initKey(_RSA_KEY*) in rsa.o
      setSeed(unsigned char*, unsigned long) in prf.o
  "___gmpz_limbs_read", referenced from:
      randBytes(unsigned char*, unsigned long) in prf.o
  "___gmpz_limbs_write", referenced from:
      rsa_shredKey(_RSA_KEY*) in rsa.o
  "___gmpz_set_ui", referenced from:
      rsa_initKey(_RSA_KEY*) in rsa.o
      setSeed(unsigned char*, unsigned long) in prf.o
  "___gmpz_size", referenced from:
      zToFile(__sFILE*, __mpz_struct*) in rsa.o
      rsa_numBytesN(_RSA_KEY*) in rsa.o
      rsa_shredKey(_RSA_KEY*) in rsa.o
      randBytes(unsigned char*, unsigned long) in prf.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

我不确定导致此错误的原因。链接器似乎是问题所在，因为我在rsa-test.c中使用rsa.c和prf.c中的函数，这就是造成这个问题的原因。

如果您想测试我的文件，请告诉我，我会发布它们。

Answer 1

您需要通过向gcc -o命令添加链接标记来链接到您正在使用的库。

您似乎正在使用GMP，因此该标志应为-lgmp。

如果涉及的其他库是OpenSSL，请尝试-lcrypto或如果您是从源代码构建的，请查看here。

gcc -o test_linked.exe rsa.o prf.o rsa-test.o -lgmp -lcrypto

Answer 2

链接时你应该包含库或共享库以及带有-L选项的optionla库路径，这样的一个例子

gcc -o binary *.o -L /path/to/libraries -llibrary

其中-llibrary看起来像这样

liblibrary.so or liblibrary.so*

链接C文件错误：链接器命令失败，退出代码为1

2 个答案: