Question

I’m trying to use the library gcrypt.h but show this error:

undefined reference to `gcry_md_get_algo_dlen’

The code is:

int algo = GCRY_MD_SHA1;                                
unsigned int hash_len = gcry_md_get_algo_dlen(algo); 
unsigned char hash[hash_len]; 

How can I fix it?

Answer 1

Make sure you have the most recent version of the library http://www.gnupg.org/download/#libgcrypt

If you have the right version make sure you added the library itself to your linker settings in Eclipse.

To do so:

Right-Click on your project -> Properties / C/C++Build / Settings / GCC C++ Linker / Libraries

There you add to libraries “gcrypt” ( you don’t at the “lib” to it )
And also make sure that ( if the lib isnt under a system path ) you add the path where the library itself lies.