为什么我不能用多个线程编译OpenSSL？ （使-j3）

Question

I'm trying to build OpenSSL. If I build it with make (1 thread), it compiles okay. But if I build it with 3 threads ( make -j3 ), I get LOTS of linker errors:

bntest.o: In function `message':
bntest.c:(.text+0x30): undefined reference to `BIO_puts'
bntest.c:(.text+0x3b): undefined reference to `BIO_puts'
bntest.o: In function `test_add':
bntest.c:(.text+0xe2): undefined reference to `BN_init'
bntest.c:(.text+0xec): undefined reference to `BN_init'
bntest.c:(.text+0xf6): undefined reference to `BN_init'
bntest.c:(.text+0x107): undefined reference to `BN_bntest_rand'
bntest.c:(.text+0x119): undefined reference to `BN_print'
bntest.c:(.text+0x126): undefined reference to `BIO_puts'
bntest.c:(.text+0x156): undefined reference to `BN_add'
bntest.c:(.text+0x166): undefined reference to `BN_add'
bntest.c:(.text+0x191): undefined reference to `BN_bntest_rand'
bntest.c:(.text+0x1d3): undefined reference to `BN_add'
bntest.c:(.text+0x1f5): undefined reference to `BN_print'
bntest.c:(.text+0x202): undefined reference to `BIO_puts'
bntest.c:(.text+0x20f): undefined reference to `BN_print'
bntest.c:(.text+0x21c): undefined reference to `BIO_puts'
bntest.c:(.text+0x264): undefined reference to `BN_free'
bntest.c:(.text+0x26e): undefined reference to `BN_free'
bntest.c:(.text+0x278): undefined reference to `BN_free'
bntest.o: In function `test_sub':
bntest.c:(.text+0x2af): undefined reference to `BN_init'
bntest.c:(.text+0x2b9): undefined reference to `BN_init'
bntest.c:(.text+0x2c3): undefined reference to `BN_init'
bntest.c:(.text+0x2e0): undefined reference to `BN_bntest_rand'
bntest.c:(.text+0x322): undefined reference to `BN_sub'
...and so on, for hundreds of lines...

To be clear, the exact sequence of commands I ran is:

$ wget https://www.openssl.org/source/openssl-1.0.1l.tar.gz
$ tar -xzf openssl-1.0.1l.tar.gz
$ cd openssl-1.0.1l
$ ./config
$ make -j3

I'm on Ubuntu 14.10 on an x64 machine.

This might be an RTFM-type question, but I haven't been able to see anywhere that says building OpenSSL with multiple threads is not supported.

So the question: Is building OpenSSL with multiple threads supported? If so, what am I doing wrong?

Answer 1

As MadScientist's comment indicates a makefile has to be designed to support parallel builds. Apparently OpenSSL is supposed to support parallel make but one of their bug reports shows that this support has on a few occasions been broken. This bug was most recently marked as fixed on December 12th, 2014, so it's possible that using a newer version of OpenSSL will fix the problem you've encountered.