Here’s a Minimal, Reproducible Example that exhibits the same problem that you experienced. I created a C library exporting a simple addition function. I also created a Cargo project to use this function. dynlink/ ├── executable │ ├── build.rs │ ├── Cargo.lock │ ├── Cargo.toml │ └── src │ └── main.rs └── library ├── … Read more
The first block, ending in “@plt”, is the procedure linkage table (https://stackoverflow.com/a/5469334/994153). The jmp *0x8049658 is an indirect branch instruction, so it actually is jumping to __libc_start_main wherever it actually ends up getting loaded in RAM at runtime. The real RAM address of __libc_start_main is found in the DYNAMIC RELOCATION RECORDS table, which is created … Read more
Typical CMake scripts like FindGLEW will define variables that specify the paths and files that your project needs. If the script can’t automatically identify the correct paths (usually because of nonstandard install location, which is fine), then it leaves these variables up to you to fill in. With command line CMake, you use the -D … Read more
To answer your questions one by one: Dynamic linking defers part of the linking process to runtime. It can be used in two ways: implicitly and explicitly. Implicitly, the static linker will insert information into the executable which will cause the library to load and resolve the necessary symbols. Explicitly, you must call LoadLibrary or … Read more
-fvisibility=hidden makes all your symbols hidden by default. What you then have to do, is choose which functions you want to be visible to users linking against your library and make them visible by marking them with a visible attribute. E.g. void __attribute__((visibility(“default”))) Exported() { // … }
You can set the runtime shared library search path using the -rpath linker option: SET(CMAKE_EXE_LINKER_FLAGS “${CMAKE_EXE_LINKER_FLAGS} -Wl,-rpath -Wl,/usr/local/lib”)
Nothing is needed at compile time, because C has a notion of separate compilation of translation units. But once all the different sources have been compiled, it is time to link everything together. The notion of shared library is not present in the standard but is it now a common thing, so here is how … Read more
Please, have a look at ld and WIN32 (cygwin/mingw). Especially, the direct linking to a dll section for more information on the behavior of -l flag on Windows ports of LD. Extract: For instance, when ld is called with the argument -lxxx it will attempt to find, in the first directory of its search path, … Read more
I needed a solution to this because I have a scriptable system that has no filesystem (using blobs from a database) and needs to load binary plugins to support some scripts. This is the solution I came up with which works on FreeBSD but may not be portable. void *dlblob(const void *blob, size_t len) { … Read more