--enable-static vs --disable-shared

Question

I understand the importance of shared vs static libraries. However, several programs I have come across recommend compiling with

--enable-static

while other recommend

--disable-shared

Are these the same thing? And if not, what is the difference?

If possible, please give an example of when to use one as opposed to the other.

Answer 1

In the common case that these are switches to a "configure" script generated by Autoconf and Libtool, then they officially mean closely-related, but different, things. --enable-static means do build static libraries; --disable-shared means don't build shared libraries.

If you want to be sure to get only static libraries, no matter what, you need to give both options. However, often just --disable-shared will have that effect, because think about the possibilities: if the package builds only static libraries by default, then --disable-shared is a no-op; if it builds both static and shared libraries by default, then you just have to turn off the shared libraries to get what you want; and if it builds only shared libraries by default, then you might think you need both options, but if you just say --disable-shared, Libtool will usually notice that it's now being asked to build nothing, assume that that couldn't possibly be what you wanted, and flip the --enable-static switch for you.