g++ undefined reference to libscrypt_scrypt (linker parameterization not the issue?)

Question

Here's my includes:

#include <iostream>
#include <string>
#include <cstring>
#include <stdio.h> //for snprintf
#include <libscrypt.h>
#include <sqlite3.h>
#include "generator.h" //has no dependencies

And here's my g++ 4.2.1 command with compilation errors:

# g++ -I/usr/local/include -L /usr/local/lib test.cpp generator.cpp -o test -lscrypt -lsqlite3
/tmp//cctxmw4C.o: In function `insertUser()':
test.cpp:(.text+0x607): undefined reference to `libscrypt_salt_gen(unsigned char*, unsigned long)'
test.cpp:(.text+0x6c3): undefined reference to `libscrypt_scrypt(unsigned char const*, unsigned long, unsigned char const*, unsigned long, unsigned long long, unsigned int, unsigned int, unsigned char*, unsigned long)'
collect2: ld returned 1 exit status

Similar C code compiles fine with GCC. I do not believe that the order of the parameters is the problem -- I have tried multiple variations, including moving the -I, -L, and both -l flags. Both scrypt and sqlite3 are C libraries, and sqlite3 throws no errors despite having the header and shared library in -I and -L respectively.

score 1 · Accepted Answer · edited May 23 '17 at 11:45

1

Look at the solution here.

Using C Libraries for C++ Programs


    extern "C"{
    void c_function_prototype();
    }

or


    extern "C" void c_function_prototype();

If you have it see "The C++ Programming Language (Stoustrup) 4th Edition" p429

edited May 23 '17 at 11:45

Community

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answered Jan 23 '17 at 21:37

london-deveoper

533
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Oh wow, I had no clue. Is the preferred way to wrap my #include with extern "C" { ... }, or is there a less messy way? – Saustin Jan 23 '17 at 21:41
1

Yes. Added to my answer – london-deveoper Jan 23 '17 at 21:52
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Great, thanks for the help and congrats on your (first?) accepted answer! – Saustin Jan 23 '17 at 21:57

g++ undefined reference to libscrypt_scrypt (linker parameterization not the issue?)

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