How to embed version information into shared library and binary?

Question

On Linux, is there a way to embed version information into an ELF binary? I would like to embed this info at compile time so it can then be extract it using a script later.

Answer 1

If you declare a variable called program_version or similar you can find out at which address the variable is stored at and then proceed to extract its value. E.g.

objdump -t --demangle /tmp/libtest.so | grep program_version
0000000000600a24 g     O .data  0000000000000004              program_version

tells me that program_version resides at address 0000000000600a24 and is of size 4. Then just read the value at that address in the file.

Or you could just write a simple program that links the library in questions and prints the version, defined either as an exported variable or a function.