How can we convert a dynamic library (filename.so) to a static library (filename.a) using gnu gcc . Can we get a static library form a dynamic library . I saw a few post in which the conversion form a static library to a dynamic library is mentioned but, unfortunately, not the other way.

Not sure, but I think you can use GNU "ar" (google it) and if you pass it the correct parameters you can take a set of object files (.o files) produced by GCC and either output a static, or dynamic library consisting of them.

I think you'd use ar to archive the original *.o object files. For a *.so file you'd need to extract the *.o files from the *.so lib first.

I don't think that ar(an archiving tool) is the right tool for extracting *.o files from a *.so file. If you run the 'file' command on a *.so library, it gives "ELF 32-bit LSB shared object" as output. This shows that dynamic libraries (*.so files) are similar to object files (*.o files) and hence it is unlikely that an archiving tool, such as ar, will be able to understand it.
However there may be a different tool which can do the conversion. Or may be it is too impractical (Just as a conversion from form a *.o file to a *.cc file is ).

You'll probably have to decompile the shared library because it's already linked. That means information required for the .o is lost because the parts become connected to the whole. In a sense, a shared library is the same as a binary except it's created under the assumption that it won't be executed directly (in most cases, the main exception being ld.*.so.)
Kevin Barry

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