shared-libraries

I am trying to compile a shared library in Linux using a Makefile created with Cmake, but running make I obtain the following error: Linking CXX shared library libcpp-lib.so /usr/bin/ld: /home/davide/Desktop/boost_1_55_0/stage/lib/libboost_system.a(error_code.o): relocation R_X86_64_32 against .rodata.str1.1 can not be used when making a shared object; recompile with -fPIC /home/davide/Desktop/boost_1_55_0/stage/lib/libboost_system.a: could not read symbols: Bad value collect2: ld returned 1 exit status make[2]: *** [libcpp-lib.so] Error 1 make[1]: *** [CMakeFiles/cpp-lib.dir/all] Error 2 make

Python has ctypes to access libraries. In PHP you write extensions for everything. Popular extensions like the one for libgd are available almost everywhere. Is there any extension which works like Python's ctypes, letting you access libraries without the need to write an PHP extension? You're looking for ffi . There is a PHP extension (irony?) called ffi . FFI stands for Foreign Function Interface , which is the generic term for when a language calls libraries written in another language. PHP 7.3 will have FFI (Foreign Function Interface). I don't think there is such a thing : in PHP, the

I'm trying to build and install my own gcc 4.7.2 in /usr/local to use in place of the gcc 4.4.6 in /usr. (This is on CentOS 6.3.) gcc makes executables and dynamic libraries that dynamically link to its own dynamic libraries, e.g. libstdc++.so. How do I build and install gcc so that the generated binaries automatically get a linker -rpath option (-rpath /usr/local/lib64) that causes dynamic libraries in /usr/local/lib64 to be linked instead of those in /usr/lib64 or /lib64? If it works properly, after I build an executable with the gcc without specifying "-Wl,-rpath=/usr/local/lib64", when I

I am trying to create a shared library in Linux. How can I pass an argument to function my_load() when library is loaded? In my C application, I make a call to test_func() then it automatically executes my_load() first before the called function then lastly it executes my_unload() #include <stdio.h> void __attribute__ ((constructor)) my_load(int argc, char *argv[]); void __attribute__ ((destructor)) my_unload(void); void test_func(void); void my_load(int argc, char *argv[]) { printf("my_load: %d\n", argc); } void my_unload(void) { printf("my_unload\n"); } void test_func(void) { printf("test

I have 4 files: 1.c , 1.h , 2.c , 2.h . I need a makefile, which will create a dynamic library (.so) from those 4 files. I have tried to write a makefile like this: library.so : 1.c 1.h 2.c 2.h but it did not work. It would be great, if someone helps me, thanks. Basile Starynkevitch Something like CC=gcc CFLAGS= -Wall -g -O -fPIC RM= rm -f .PHONY: all clean all: library.so clean: $(RM) *.o *.so library.so: 1.o 2.o $(LINK.c) -shared $< -o $@ 1.o: 1.c 1.h 2.h 2.o: 2.c 1.h 2.h But this is untested! I am assuming Linux with GNU make , and a directory containing only the source code of your library

Shared objects (*.so) in Unix-like systems are inefficient because of the symbol interposition: Every access to a global variable inside the .so needs a GOT lookup, and every call from one function to another inside the .so needs a PLT lookup. I was therefore happy to see that gcc version 5.1 has added the option -fno-semantic-interposition. However, when I try to make a .so where one function calls another without using a PLT, I get the error message: relocation R_X86_64_PC32 against symbol `functionname' can not be used when making a shared object; recompile with -fPIC I expected the option

I have a project where I have one static library libhelper.a and another with my actual shared object library, libtestlib.so . My goal is to link libhelper.a into libtestlib.so . Is that possible on Linux/BSD? When I tried and created a test program I got the following errors: ./prog1:/usr/local/lib/libtestlib.so.1.0: undefined symbol '' My guess is that this is occurring because libhelper.a was not compiled with -fPIC while libtestlib.so was. What is the proper way to build programs that use shared libraries that also have dependancies on static libraries? Thanks! My goal is to link libhelper

I'm using dlopen to load a shared library at run time dlopen("SharedLibarary1.so", RTLD_NOW | RTLD_GLOBAL); In that shared object I refer to a const char* defined in another shared library "SharedLibarary2.so". The Executable, and both the libraries are built using -rdynamic. But I still get the run time error when using dlopen: "/usr/lib/SharedLibarary1.so: undefined symbol" and points to the mangled const char* has the undefined symbol. Whith GDB "info share" I can see that the second library is not loaded at the point of the error. How ever that problem goes away if I do a dlopen on the