Static linking produces a larger executable file than dynamic linking because it has to compile all of the library code directly into the executable. The benefit is a reduction in overhead from no longer having to call functions from a library, and anywhere from somewhat to noticeably faster load times. A dynamically linked executable will … Read more
The problem is that replacing call printf@PLT with call [printf@GOTPLT] requires that the compiler knows that the function printf exists in a shared library and not a static library (or even in just a plain object file). The linker can change call printf into call printf@PLT, jmp printf into jmp printf@PLT or even mov eax, … Read more
You can specify the relationship between a and b by adding target_link_libraries(b a) From the docs: Library dependencies are transitive by default. When this target is linked into another target then the libraries linked to this target will appear on the link line for the other target too. So, if you specify a as a … Read more
When you ship a binary, it’s good to provide means for the users to accommodate the binary to the specifics of their own system, among other things, adjusting library search paths. A user can generally tweak LD_LIBRARY_PATH and /etc/ld.so.conf, both of which are with lower precedence than DT_RPATH, i.e. you can’t override what is hardcoded … Read more
I always do it this way: #define _GNU_SOURCE #include <stdio.h> #include <dlfcn.h> static void* (*real_malloc)(size_t)=NULL; static void mtrace_init(void) { real_malloc = dlsym(RTLD_NEXT, “malloc”); if (NULL == real_malloc) { fprintf(stderr, “Error in `dlsym`: %s\n”, dlerror()); } } void *malloc(size_t size) { if(real_malloc==NULL) { mtrace_init(); } void *p = NULL; fprintf(stderr, “malloc(%d) = “, size); p = … Read more
There are several ways to solve this: Pass -Bsymbolic or -Bsymbolic-functions to the linker. This has a global effect: every reference to a global symbol (of function type for -Bsymbolic-functions) that can be resolved to a symbol in the library is resolved to that symbol. With this you lose the ability to interpose internal library … Read more
It can be either. Only iOS8+ will allow dynamic frameworks in the app bundle, however. The way to find out is to look in the .framework and use the file command on the main file: $ cd iOS/Crashlytics.framework $ ls -l total 9984 -rwxr-xr-x 1 andy staff 4710656 11 Sep 17:11 Crashlytics drwxr-xr-x 8 andy … Read more
On OS X, calls made within the library are automatically direct calls and do not go through the dyld stub. The evidence to the fact is that if you want to be able to inject alternative functions to service a call, you’ll need to use interposable to force indirect access to the symbols and force … Read more
-Wl,–no-undefined linker option can be used when building shared library, undefined symbols will be shown as linker errors. g++ -shared -Wl,-soname,libmylib.so.5 -Wl,–no-undefined \ -o libmylib.so.1.1 mylib.o -lthirdpartylib
See question 3544035. Also discussed here and there. It depends on what use you will have for your static library. If you only want to link it into programs, it doesn’t need PIC code (libtool calls that a convenience library, because you could pretty much do without it, it simply helps get your compilation process … Read more