dlopen | 易学教程

dlopen vs linking overhead

阅读更多关于 dlopen vs linking overhead

问题 Suppose I have a library - foo.so . When building my binary (which needs this library), I can either (1) link foo.so , or, (2) within the program source code, dlopen this library and then call functions provided by this library Is there any performance difference between (1) and (2) when I call a function from the library? Note that I am aware that there will be different initialization characteristics (like the cost of the dlopen , overhead for first usage of a symbol etc) but in the steady

dlopen() from sandbox in iOS 10 is blocked

阅读更多关于 dlopen() from sandbox in iOS 10 is blocked

问题 i'm using dlopen() to load dynamic framework from documents directory, it's working good below iOS10, but in iOS10 it does not work anymore，and console's log is: file system sandbox blocked mmap() of '/var/mobile/Containers/Data/Application/71EB4588-A83F-4AF0-9409-DD09AFB2CA77/Documents/MyDylib.framework/MyDylib' how can i solve this problem? 回答1: in iOS10 the framework cannot save to the Documents dir or subdir. you must put the framework under to the YouAppName.app/ 来源： https:/

dlopen and global variables in C/C++

阅读更多关于 dlopen and global variables in C/C++

问题 Due to some restrictions I am being forced to load a library written in C at runtime. A third party provides two library to me as static archives which we turn into shared objects. The application I'm working with loads one of the libraries at runtime based on some hardware parameters. Unfortunately one of the libraries is configured largely with global variables. I am already using dlsym to load function references but can I used dlsym to load references to these global variables as well?

使用dlopen和dlsym来使用C++中的类

阅读更多关于使用dlopen和dlsym来使用C++中的类

【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 使用dlopen和dlsym来使用C++中的类 2008-08-09 23:43:37 分类：一般来说，dlopen和dlsym是来处理C库中的函数的，对于C++中存在的name mangle问题，类的问题就不易处理，看下文你会有所收获。转载自： http://www.linuxsir.org/bbs/printthread.php?t=266890 C++ dlopen mini HOWTO 中译版 [原创] C++ dlopen mini HOWTO 作者：Aaron Isotton <aaron@isotton.com> 2006-03-16 译者：Lolita@linuxsir.org 2006-08-05 ------------------------------------------------ 摘要　　如何使用dlopen API动态地加载C++函数和类 ------------------------------------------------ 目录　　介绍　　　　版权和许可证　　　　不承诺　　　　贡献者　　　　反馈　　　　术语　　问题所在　　　　Name Mangling 　　　　类　　解决方案　　　　extern "C" 　　　　加载函数　　　　加载类　

dlopen() error image not found

阅读更多关于 dlopen() error image not found

问题 I have software that first loads a .dylib lets call libFirst.dylib using the following command: void* handle = dlopen(path.c_str(), RTLD_LAZY | RTLD_GLOBAL); Later on inside a function from the loaded libFirst.dylib I attempt to load another .dylib using the same command but for libSecond.dylib, the loading of this shared library gives me the following warnings in my Xcode console: error warning: Ignored unknown object module at 0x129310 with type 0x8a8399 dlerror: dlopen(/path/libSecond

Dynamic Loading Without extern “C”

阅读更多关于 Dynamic Loading Without extern “C”

问题 I'd like to use libdl to dynamically load C++ in general. The problem is identifying symbols at runtime that have been name mangled. As described here, one solution is to remove name mangling by using extern "C". http://www.tldp.org/HOWTO/C++-dlopen/theproblem.html This solution has the drawback of limiting dynamically loaded resources to C style interfaces. Dynamically loaded functions cannot, for instance, be overloaded functions. What is a good way to overcome this limitation? One possible

C++: dlclose doesn't unload the shared library

阅读更多关于 C++: dlclose doesn't unload the shared library

问题 I have a shared library loaded using dlopen (with the flags RTLD_NOW | RTLD_GLOBAL ). If this library is using functions from the main program, then it does not unload. So I end up with the same code for this shared lib, even if I unloaded (using dlclose ), changed, compiled, (re)load it. My goal is actually to reload the same library after making changes to it, so that I do not have to relaunch the whole program to test out my code. I am using g++ 4.2.3, on Linux Ubuntu 10.04. (edit) solved:

LINUX下动态链接库的使用（dlopen/dlsym/dlclose/dlerror）

阅读更多关于 LINUX下动态链接库的使用（dlopen/dlsym/dlclose/dlerror）

dlopen 功能：打开一个动态链接库包含头文件： #include <dlfcn.h> 函数定义： void * dlopen( const char * pathname, int mode ); 函数描述：在dlopen的（）函数以指定模式打开指定的动态连接库文件，并返回一个句柄给调用进程。使用dlclose（）来卸载打开的库。 mode：　　 RTLD_LAZY 暂缓决定，等有需要时再解出符号　　RTLD_NOW 立即决定，返回前解除所有未决定的符号。　　RTLD_LOCAL 　　RTLD_GLOBAL 允许导出符号　　RTLD_GROUP 　　RTLD_WORLD 返回值: 　　打开错误返回NULL 　　成功，返回库引用编译时候要加入 -ldl (指定dl库) 　　例如　　gcc test.c -o test -ldl 　　dlopen()是一个强大的库函数。该函数将打开一个新库，并把它装入内存。该函数主要用来加载库中的符号，这些符号在编译的时候是不知道的。比如 Apache Web 服务器利用这个函数在运行过程中加载模块，这为它提供了额外的能力。一个配置文件控制了加载模块的过程。这种机制使得在系统中添加或者删除一个模块时，都不需要重新编译了。　　可以在自己的程序中使用 dlopen()。dlopen() 在 dlfcn.h 中定义，并在

Receive “undefined symbol” error when loading library with dlopen

阅读更多关于 Receive “undefined symbol” error when loading library with dlopen

问题 I'm writing some code that uses dynamic shared libraries as plugins. My command line for building the shared libraries looks like: cc -shared -fPIC -o module.so -g -Wall module.c Within the module, I can call functions that are in any other shared library that has been loaded within the main executable. However I cannot access (exported) functions that are in the executable itself (I get undefined symbol errors). My call to dlopen looks like this: void *handle = dlopen(plugin, RTLD_NOW); Can

library path when dynamically loaded?

阅读更多关于 library path when dynamically loaded?

问题 How can I get the path of the shared library from within the library itself? In other words, let's say that library X is loaded using dlopen() , how can I get access to the path that was used to load the said library from within the library itself? Note that I cannot have the agent that loaded the library in the first place hand me this parameter. UPDATED: Here is way that works with static variables: std::string wdir; namespace { class dynamic_library_load_unload_handler { public: dynamic