I have a shared library project that is built from 4 static libraries (`.a`) and one object (`.o`) file. I am trying to add the `-fvisibility=hidden` option to restrict symbols in the output to only those that I mark in the source with an \__attribute\__.

I&#39;ve added the `-fvisibility=hidden` option to the compile options for the `.so` project (which covers the `.o` file) and for the `.a` projects.

The symbols in the object file are removed as expected from the final `.so`. However the symbols from the `.a` projects are all still in the final `.so` file. Adding the `-fvisibility=hidden` option to the `.so` link command has no effect.

What am I doing wrong?

My purpose here is to remove from the `.so` all symbols except the interface functions to the library.

EDIT: I actually used a [version map][1] to solve this for now. However it requires continued maintenance of the version script as external symbols change. Accepted answer has a better idea.


  [1]: http://sourceware.org/ml/binutils/2000-05/msg00305.html

How to apply -fvisibility option to symbols in static libraries?

I know an `.so` file is a kind of dynamic library (lots of threads can share such libraries so there is no need to have more than one copy of it in memory). But what is the difference between `.a` and `.la`? Are these all static libraries?

If dynamic libs have big advantages over static ones, why there are still lots of static libraries? When should I try to build code into `.so` or `.a`?

    [mirror@home ins_openvpn]$ ls lib/openvpn/plugins/ -l
    total 96
    -rw-r--r-- 1 mirror mirror 22892 Sep  2 23:25 openvpn-plugin-auth-pam.a
    -rwxr-xr-x 1 mirror mirror   931 Sep  2 23:25 openvpn-plugin-auth-pam.la
    -rwxr-xr-x 1 mirror mirror 23621 Sep  2 23:25 openvpn-plugin-auth-pam.so
    -rw-r--r-- 1 mirror mirror 17228 Sep  2 23:25 openvpn-plugin-down-root.a
    -rwxr-xr-x 1 mirror mirror   932 Sep  2 23:25 openvpn-plugin-down-root.la
    -rwxr-xr-x 1 mirror mirror 18805 Sep  2 23:25 openvpn-plugin-down-root.so

What&#39;s the difference between .so, .la and .a library files?

I know very little about DLL&#39;s and LIB&#39;s other than that they contain vital code required for a program to run properly - libraries. But why do compilers generate them at all? Wouldn&#39;t it be easier to just include all the code in a single executable? And what&#39;s the difference between DLL&#39;s and LIB&#39;s?

DLL and LIB files - what and why?

I have a binary file - Windows static library (*.lib).  
Is there a simple way to find out names of the functions and their interface from that library ?

Something similar to `emfar` and `elfdump` utilities (on Linux systems) ?

How to See the Contents of Windows library (*.lib)

I have an existing iOS app and want to add a large chunk of code that I&#39;ve been developing as another project just for ease of testing. The new chunk basically deals with saving an image to various sharing services, etc.. Because that sharing code needs a lot of testing and future updating, I was wondering what the best way to incorporate that code chunk into my existing app.

I don&#39;t know if it should be a static library, dynamic library or a framework, and honestly, I&#39;m not really sure what the difference is, or how I should go about it and get it set up in Xcode.

All I know is that I need/want to keep a separate testing and updating app for the sharing code and have the main app use it.


Library? Static? Dynamic? Or Framework? Project inside another project

It feels  strange to me to use `-Wl,-Bstatic` in order to tell `gcc` which libraries I want to link with statically. After all I&#39;m telling `gcc` directly all other information about linking with libraries (`-Ldir`, `-llibname`).

Is it possible to tell the gcc driver directly which libraries should be linked statically?

**Clarification:** I know that if a certain library exists only in static versions it&#39;ll use it  without `-Wl,-Bstatic`, but I want to imply `gcc` to prefer the static library. I also know that specifying the library file directly would link with it, but I prefer to keep the semantic for including static and dynamic libraries the same.

Telling gcc directly to link a library statically

I have a question: How to compile a static library in Linux with `gcc`, i.e. I need to compile my source code into a file named out.a. Is it sufficient to simply compile with the command `gcc -o out.a out.c`? I&#39;m not quite familiar with `gcc`, hope anyone can give me a hand.

How to compile a static library in Linux?

Can you guide me how to properly link static library to iPhone project. I use static library project added to app project as direct dependency (target -&gt; general -&gt; direct dependencies) and all works OK, but categories. A category defined in static library is not working in app. 

So my question is how to add static library with some categories into other project? 

And in general, what is best practice to use in app project code from other projects?

Why do we use use_frameworks! in CocoaPods?

What is the difference between static and shared libraries?

I use Eclipse and there are several project types including Static Libraries and Shared Libraries? Does one have an advantage over the other?

Difference between static and shared libraries?

I am quite new to xcode and objective-c. I want to ask a very basic question.

I saw that when &quot;linking binary to libraries&quot; in project settings, there are differences about framework and libraries, imported from other projects in workspace.

First question, why is there a framework? And why is there a library? Cannot my library be a framework?

And then, from a *.h* file, how can I call classes from my imported static library?

I suppose there must be a prefix, but I couldn&#39;t find it.
Neither &lt;ProjName/Myclass.h&gt; nor &quot;ProjName/Myclass.h&quot; are working.

Please, be as specific as you can.

Thanks

Difference between framework and static library in xcode4, and how to call them

How can I statically link only a some specific libraries to my binary when linking with GCC?

`gcc ... -static ...` tries to statically link **all** the linked libraries, but I haven&#39;t got the static version of some of them (eg: libX11).

static linking only some libraries

I have to admit that with the release of iOS 8 I am a bit confused about dynamic and static frameworks in iOS.

I am looking for a way to distribute a library that I created, and I need to support iOS 7 and above. (Note: This will be a proprietary framework. I cannot use cocoa pods, and I also cannot distribute the source). Here is what I already know:

- iOS 8 introduced &quot;embedded frameworks&quot; for iOS, but, as I understand, they do not work for iOS 7, only for iOS 8 and above.
- I have the option of distributing my library as a static library (.a file) and also distribute the headers. I know that this is a common way of dealing with the situation, but I would like to find something simpler than that (and also to bundle some resources with it, if possible).
- I have also found that iOS 7 does not support dynamic .framework libraries (only static) because it doesn&#39;t support dynamic linking. But iOS 8 does, as well as static linking.

And here are my questions regarding this information:

- I saw that I can create a .framework target, and make it static, by changing the Mach-O type to &quot;static library. Would that be enough in order to support iOS 7 without any problems, and also to distribute my library as a .framework bundle? If so, why is &quot;embedded frameworks&quot; in iOS 8 that big of a deal, as many resources on the internet are suggesting? Am I missing something?
- Is it necessary to codesign the .framework just as I do with any other application I make?
- What if I need to include other resources (like Core Data or Images) with my .framework file? Will I need to make a separate .bundle file for that?

iOS Static vs Dynamic frameworks clarifications

I have a small project with a Makefile which I&#39;m trying to convert to CMake, mostly just to get experience with CMake. For purposes of this example, the project contains a source file (C++, though I don&#39;t think the language is particularly relevant) and a static library file which I&#39;ve copied from elsewhere. Assume for argument&#39;s sake that the source code to the library is unavailable; I only have the .a file and the corresponding header.

My handmade Makefile contains this build rule:

    main: main.o libbingitup.a
        g++ -o main main.o libbingitup.a

which works fine. How do I tell CMake to reproduce this? Not literally this exact makefile, of course, but something that includes an equivalent linking command. I&#39;ve tried the obvious but naive ways, like

    add_executable(main main.cpp libbingitup.a)

or

    add_executable(main main.cpp)
    target_link_libraries(main libbingitup.a)

as well as various things with `link_directories(.)` or `add_library(bingitup STATIC IMPORTED)` etc. but nothing so far that results in a successful linkage. What should I be doing?

---

Version details: CMake 2.8.7 on Linux (Kubuntu 12.04) with GCC 4.6.3

How do I tell CMake to link in a static library in the source directory?

I have 2 static Linux libraries, created by `ar cr`, `libabc.a` and `libxyz.a`.&lt;br&gt;
I want to merge them into one static library `libaz.a`.&lt;br&gt;
How can I do this.

I want to create a merged static library,  not to give both libraries to final link of applications.

How to merge two &quot;ar&quot; static libraries into one?

I have a problem with linking my mixed language framework to a project.&lt;p&gt;
1. I create a framework with Swift and Objective-C classes.
1. The main logic was stored in the Swift file. For example the class with a method that calls NSLog(&quot;Swift log was called&quot;).
1. Objective-C file has a class that has a method in which I create an instance of Swift class and call Swift-log method.
1. I link this framework with my Objective-C project, I can call all that I need in this project, but when I want to build this project I receive error `linker command failed with exit code 1 (use -v to see invocation)`
  
    And warnings:
```
ld: warning: Could not find auto-linked library &#39;swiftFoundation&#39;
ld: warning: Could not find auto-linked library &#39;swiftDarwin&#39;
ld: warning: Could not find auto-linked library &#39;swiftCoreFoundation&#39;
ld: warning: Could not find auto-linked library &#39;swiftCore&#39;
ld: warning: Could not find auto-linked library &#39;swiftCoreGraphics&#39;
ld: warning: Could not find auto-linked library &#39;swiftObjectiveC&#39;
ld: warning: Could not find auto-linked library &#39;swiftDispatch&#39;
ld: warning: Could not find auto-linked library &#39;swiftSwiftOnoneSupport&#39;
```

I also saw the solution with importing empty Swift-file, but it necessary to make a project without any trash.

Why do I get iOS linker errors with my static libraries?

I need to deploy a C++ application built on Ubuntu 12.10 with GCC 4.7&#39;s libstdc++ to systems running Ubuntu 10.04, which comes with a considerably older version of libstdc++.

Currently, I&#39;m compiling with `-static-libstdc++ -static-libgcc`, as suggested by this blog post: [Linking libstdc++ statically](https://web.archive.org/web/20160313071116/http://www.trilithium.com/johan/2005/06/static-libstdc/). The author warns against using any dynamically-loaded C++ code when compiling libstdc++ statically, which is something I haven&#39;t yet checked. Still, everything seems to be going smoothly so far: I can make use of C++11 features on Ubuntu 10.04, which is what I was after.

I note that this article is from 2005, and perhaps much has changed since then. Is its advice still current? Are there any lurking issues I should be aware of?

Linking libstdc++ statically: any gotchas?

What is inside of a .lib file of Static library, Statically linked dynamic library and dynamically linked dynamic library?

How come there is no need for a .lib file in dynamically linked dynamic library and also that in static linking, the .lib file is nothing but a .obj file with all the methods. Is that correct?

What is inside .lib file of Static library, Statically linked dynamic library and dynamically linked dynamic library?

&gt; ## Alternate titles to aid search
&gt; - Xcode can&#39;t find header 
&gt; - Missing .h in Xcode
&gt; - Xcode .h file not found
&gt; - lexical or preprocessor issue file not found

I&#39;m working on an iOS application project which came from Xcode 3.  I have now moved to Xcode 4 my project builds a number of static libraries.

Those static libraries also declare public headers and those headers are used by the application code. In Xcode 3.x the headers were copied (as a build phase) to the `public headers directory`, then in the application project the `public headers directory` was added to the `headers search list`.

Under Xcode 4 the build directory is moved to `~/Library/Developer/Xcode/DerivedData/my-project`. 

The problem is how do I reference this new location in the headers search settings? It seems that:

- `public headers directory` is relative to `DerivedData` directory, but
- `headers search` directory is relative to something else (possibly the project location)

How should I set up a static library target for iOS development in Xcode 4 that will ensure the header files are made available to the clients that use the static library when trying to compile as a dependancy?

Xcode 4 can&#39;t locate public header files from static library dependency

I am attempting to use the libtommath library. I&#39;m using the NetBeans IDE for my project on Ubuntu linux. I have downloaded and built the library, I have done a &#39;make install&#39; to put the resulting .a file into /usr/lib/ and the .h files into /usr/include

It appears to be finding the files appropriately (since I no longer get those errors, which I did before installing into the /usr directories).

However, when I create a simple main making a call to mp_init (which is in the library), I get the following error when I attempt to make my project:

    mkdir -p build/Debug/GNU-Linux-x86
    rm -f build/Debug/GNU-Linux-x86/main.o.d
    gcc -c -g -MMD -MP -MF build/Debug/GNU-Linux-x86/main.o.d -o build/Debug/GNU-Linux-x86/main.o main.c
    mkdir -p dist/Debug/GNU-Linux-x86
    gcc -o dist/Debug/GNU-Linux-x86/cproj1 build/Debug/GNU-Linux-x86/main.o
    build/Debug/GNU-Linux-x86/main.o: In function &#39;main&#39;:
    /home/[[myusername]]/NetBeansProjects/CProj1/main.c:18: undefined reference to `mp_init&#39;
    collect2: ld returned 1 exit status
    make[2]: *** [dist/Debug/GNU-Linux-x86/cproj1] Error 1

So, it looks like the linker can&#39;t find the function within the library, however it IS there, so I just don&#39;t know what could be causing this.

I get the same error if I type the gcc command directly and skip the makefile, I also made sure the static library got compiled with gcc as well.

Edited to Add:

I get these same errors if I do the compile directly and add the library with -l or -L:

    $ gcc -l /usr/lib/libtommath.a main.c 
    /usr/bin/ld: cannot find -l/usr/lib/libtommath.a
    collect2: ld returned 1 exit status
    
    $ gcc -llibtommath.a main.c 
    /usr/bin/ld: cannot find -llibtommath.a
    collect2: ld returned 1 exit status
    
    $ gcc -Llibtommath.a main.c 
    /tmp/ccOxzclw.o: In function `main&#39;:
    main.c:(.text+0x18): undefined reference to `mp_init&#39;
    collect2: ld returned 1 exit status
    
    $ gcc -Llibtommath.a main.c 
    /tmp/ccOxzclw.o: In function `main&#39;:
    main.c:(.text+0x18): undefined reference to `mp_init&#39;
    collect2: ld returned 1 exit status

I am very rusty on this stuff, so I&#39;m not sure I&#39;m using the right command here, in the -L examples are the libraries being found? If the library isn&#39;t being found how on earth do I get it to find the library? It&#39;s in /usr/lib, I&#39;ve tried it with the .a file in the current directory, etc.  Is there an environment variable I need to set?  If so, how, etc.

I&#39;ve tried a completely different library (GMP) and had the EXACT same problem. This has got to be some kind of Ubuntu environment issue? Anyone have any idea how to fix this?

Trying to include a library, but keep getting &#39;undefined reference to&#39; messages

During compilation and linking, what is use of .exp? What is the difference between .lib and .dll? I know that .lib will be used, while linking and .dll will be used when running the program. But what exactly is the difference between .lib and .dll?

Does .lib file not contain the code for the functions coming from .dll files?
What is the need for using two separate files?

Please clarify.

What is the use of .exp and what is the difference between .lib and .dll?

I upgraded [Xcode][1] version and when using external static libraries, I get this message:

&gt; ld: file is universal (3 slices) but does not contain a(n) armv7s slice: /file/location for architecture armv7s
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Is there any way to bypass this and add support to the library if the developer of the library hasn&#39;t updated their library yet?

  [1]: http://en.wikipedia.org/wiki/Xcode


File is universal (three slices), but it does not contain a(n) ARMv7-s slice error for static libraries on iOS, anyway to bypass?

I&#39;m Trying to Link a static Library to a shared library , I&#39;m Getting the Following error

&lt;pre&gt;
/usr/bin/ld: ../../../libraries/log4cplus/liblog4cplus.a(fileappender.o): relocation R_X86_64_32S against `a local symbol&#39; can not be used when making a shared object; recompile with -fPIC
../../../libraries/log4cplus/liblog4cplus.a: could not read symbols: Bad value
collect2: ld returned 1 exit status
&lt;/pre&gt;

But this worked on a 32bit machine without any such error. I tried adding The `-fPIC` flags manually to the Makefile that too didn&#39;t solve the problem

I tried the `-whole-archive` flag as suggested [here](https://stackoverflow.com/questions/14889941/link-a-static-library-to-a-shared-one-during-build) but with no success.

&lt;pre&gt; 
/usr/bin/ld: ../../../libraries/log4cplus/liblog4cplus.a(appenderattachableimpl.o): relocation R_X86_64_32S against `vtable for log4cplus::spi::AppenderAttachable&#39; can not be used when making a shared object; recompile with -fPIC
../../../libraries/log4cplus/liblog4cplus.a(appenderattachableimpl.o): could not read symbols: Bad value
collect2: ld returned 1 exit status
&lt;/pre&gt;

### Creation of liblog4cplus.a: ###
 1. `unzip log4cplus-1.1.0.zip`
 2. `./configure --enable-static=yes --enable-threads=yes`
 3. `vi Makefile` and added -fPIC to CXXFLAGS and CFLAGS
 4. `make`

### Then for Compiling my shared library: ###

 1. `g++ -frtti -w  -c -fPIC -I&quot;Include_Directory&quot; myfile.cpp`
 2. `g++ -shared -fPIC -frtti -I&quot;Include_Directory&quot; -o mysofile.so myfile.o -Wl,--whole-archive &quot;../../../libraries/log4cplus/liblog4cplus.a&quot; -Wl,--no-whole-archive -ldl`


&quot;relocation R_X86_64_32S against &quot; linking Error

I&#39;m writing C++ code on a mac. Why do I get this error when compiling?:

&gt; Undefined symbols for architecture i386:   &quot;Log::theString&quot;,
&gt; referenced from:
&gt;       Log::method(std::string) in libTest.a(Log.o) ld: symbol(s) not found for architecture i386 clang: error: linker command failed with
&gt; exit code 1 (use -v to see invocation)

Not sure if my code is wrong or I have to add additional flags to Xcode. My current XCode configurations are the default ones for a &#39;static library&#39; project.

My code:  

Log.h------------

    #include &lt;iostream&gt;
    #include &lt;string&gt;
    
    using namespace std;
    
    class Log{
    public:
        static void method(string arg);
    private:
        static string theString ;
    };

Log.cpp ----

    #include &quot;Log.h&quot;
    #include &lt;ostream&gt;
    
    void Log::method(string arg){
        theString = &quot;hola&quot;;
        cout   &lt;&lt; theString &lt;&lt; endl; 
    }

I&#39;m calling the &#39;method&#39; from a test code, in this way:
&#39;Log::method(&quot;asd&quot;):&#39;

thanks for your help.

static variable link error

I just built a static library for iOS with the build setting for Architectures set to `$(ARCHS_STANDARD_INCLUDING_64_BIT)`. 

I want to make sure that the .a library is properly including that architecture, but when i run `lipo -info` on it, I see:

&gt; Architectures in the fat file: library.a are: armv7 armv7s
&gt; (cputype (16777228) cpusubtype (0))

Does this mean that arm64 isn&#39;t included? If the lipo command can&#39;t tell me, is there another way to tell?

I&#39;m running Xcode 5 with the latest Command Line Tools installed.

How to check if a static library is built for 64-bit?

I&#39;m building a Cocoa Touch Static Library. How should I decide whether to copy a header file as public, private, or project?

Xcode: Copy Headers: Public vs. Private vs. Project?

I&#39;ve a program which links to many libraries. `g++`, by default, prefers to link to shared libraries, even if the corresponding archive exists.

How can I change this preference to prefer static archives over dynamic libraries, if a static archive exists?

Note, I used `-static` option, but it tries to find static archive for all libraries which is not what I want.


g++ linker: force static linking if static library exists?

I just updated my iPhone 4S software to iOS 7 Beta 2 while I was in the middle of putting the final touches on a new app (Phonegap).. not a good idea!

After it was done Xcode didn&#39;t detect my iPhone so I installed Xcode 5 beta. After tinkering around with it I finally got it to detect my phone. The only problem now is there is an error with the architecture used.

Here are the errors being produced:

    ld: warning: ignoring file /Users/-----------/Library/Developer/Xcode/DerivedData/testtest-bmnbmujiosugcmgeiceofgcfmsec/Build/Products/Debug-iphoneos/libCordova.a, file was built for archive which is not the architecture being linked (armv7s): /Users/--------/Library/Developer/Xcode/DerivedData/testtest-bmnbmujiosugcmgeiceofgcfmsec/Build/Products/Debug-iphoneos/libCordova.a
    Undefined symbols for architecture armv7s:
      &quot;_OBJC_METACLASS_$_CDVCommandDelegateImpl&quot;, referenced from:
          _OBJC_METACLASS_$_MainCommandDelegate in MainViewController.o
      &quot;_CDVLocalNotification&quot;, referenced from:
          -[AppDelegate application:didReceiveLocalNotification:] in AppDelegate.o
      &quot;_OBJC_CLASS_$_CDVCommandDelegateImpl&quot;, referenced from:
          _OBJC_CLASS_$_MainCommandDelegate in MainViewController.o
      &quot;_OBJC_CLASS_$_CDVCommandQueue&quot;, referenced from:
          _OBJC_CLASS_$_MainCommandQueue in MainViewController.o
      &quot;_OBJC_METACLASS_$_CDVViewController&quot;, referenced from:
          _OBJC_METACLASS_$_MainViewController in MainViewController.o
      &quot;_OBJC_METACLASS_$_CDVCommandQueue&quot;, referenced from:
          _OBJC_METACLASS_$_MainCommandQueue in MainViewController.o
      &quot;_CDVPluginHandleOpenURLNotification&quot;, referenced from:
          -[AppDelegate application:handleOpenURL:] in AppDelegate.o
      &quot;_OBJC_CLASS_$_CDVViewController&quot;, referenced from:
          _OBJC_CLASS_$_MainViewController in MainViewController.o
    ld: symbol(s) not found for architecture armv7s
    clang: error: linker command failed with exit code 1 (use -v to see invocation)

Any ideas on what the architecture should be changed to in order to get it to work on my phone? (it&#39;s working fine on the emulator)



After update to Xcode 5 - ld: symbol(s) not found for architecture armv7 or armv7s linker error

I am constantly getting this warning while building my android studio code using terminal command `gradle clean assembleRelease`:

`Unable to strip library &#39;lib.so&#39; due to missing strip tool for ABI &#39;ARMEABI&#39;. Packaging it as is.`

Please help me on how to get this warning resolved.

Note: I know this won&#39;t affect the behaviour of my app, but my APK is too bulky and this will surely help me reduce APK size. So I need this resolved.

Android Studio : Missing Strip Tool

I&#39;m trying to make a static library from a class but when trying to use it, I always get errors with undefined references on anything. The way I proceeded was creating the object file like 

    g++ -c myClass.cpp -o myClass.o

 and then packing it with 

    ar rcs myClass.lib myClass.o

There is something I&#39;m obviously missing generally with this. I bet it&#39;s something with symbols.
Thanks for any advice, I know it&#39;s most probably something I could find out if reading some tutorial so sorry if bothering with stupid stuff again :)


edit:
----------
myClass.h:

    class myClass{
    	public:
    		myClass();
    		void function();
    };

myClass.cpp:


    #include &quot;myClass.h&quot;
    
    myClass::myClass(){}
    void myClass::function(){}

program using the class:

    #include &quot;myClass.h&quot;
    
    int main(){
    myClass mc;
    mc.function();
    
    return 0;
    }

finally I compile it like this:

    g++ -o main.exe -L. -l myClass main.cpp

the error is just classic:

    C:\Users\RULERO~1\AppData\Local\Temp/ccwM3vLy.o:main.cpp:(.text+0x31): undefined
     reference to `myClass::myClass()&#39;
    C:\Users\RULERO~1\AppData\Local\Temp/ccwM3vLy.o:main.cpp:(.text+0x3c): undefined
     reference to `myClass::function()&#39;
    collect2: ld returned 1 exit status

c++ undefined references with static library

I&#39;m trying to understand this LIB file business on Microsoft Windows, and I&#39;ve just made a discovery that will - I hope - dispel the confusion that hitherto has prevented me from getting a clear grasp of the issue. To wit, LIB files are not the one kind of file that their file extension suggests they are.

    :: cd &quot;C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Lib&quot;
    
    :: lib /nologo /list Ad1.Lib
    obj\i386\activdbgid.obj
    obj\i386\activscpid.obj
    obj\i386\ad1exid.obj
    obj\i386\dbgpropid.obj
    obj\i386\dispexid.obj
    
    :: lib /nologo /list oledb.lib
    o:\winmain.obj.x86fre\enduser\…\oledb\uuid\objfre\i386\oledbiid.obj
    o:\winmain.obj.x86fre\enduser\…\oledb\uuid\objfre\i386\oledbnewiid.obj
    o:\winmain.obj.x86fre\enduser\…\oledb\uuid\objfre\i386\cmdtreeiid.obj
    o:\winmain.obj.x86fre\enduser\…\oledb\uuid\objfre\i386\oledbdepiid.obj
    
    :: lib /nologo /list AdvAPI32.Lib | sort | uniq -c
        731 ADVAPI32.dll

The first two examples contain object files (appearing as relative or absolute paths when displayed by the `lib.exe` utility). The third example, however, only contains 731 references to a DLL. (I guess `lib.exe` isn&#39;t designed to display more useful information for this kind of file.)

Some contain object files, and they are static libraries. Others contain symbols, and they are import libraries. (There&#39;s a [short explanation here](https://stackoverflow.com/questions/2240737/2240777#2240777).)

So static libraries appear to be the equivalents of `.a` files on Linux, and DLLs appear to map to `.so` files on Linux. (By the way, how would import libraries fit into this Windows/Linux equivalence picture?)

Now I&#39;m wondering why this is so? Why did Microsoft decide to give import libraries the same file extension as static libraries? (I understand that historically, static libraries were first, like primitive forms of life preceded more complex forms.) Why wouldn&#39;t they say, okay, here&#39;s these new kind of libraries, they shall be referred to as import libraries, and they shall bear the file extension `.ILB` (or whatever)?

Why are LIB files beasts of such a duplicitous nature?

I have a third-party library which consists mainly of a large number of static (`.a`) library files.  I can compile this into a single `.a` library file, but I really need it to be a single `.so` shared library file.

Is there any way to convert a static `.a` file into a shared `.so` file?  Or more generally is there a good way to combine a huge number of static `.a` files with a few `.o` object files into a single `.so` file?

Convert a Static Library to a Shared Library?

I have a static library, say `mystaticlib.a`. I want to see its contents, such as the number of object files inside it. 

How can I do this on gcc?

Contents of a static library

The only real use of the `--whole-archive` linker option that I have seen is in creating shared libraries from static ones. Recently I came across Makefile(s) which always use this option when linking with in house static libraries. This of course causes the executables to unnecessarily pull in unreferenced object code. My reaction to this was that this is plain wrong, am I missing something here ? 

The second question I have has to do with something I read regarding the whole-archive option but couldn&#39;t quite parse. Something to the effect that  `--whole-archive` option should be used while linking with a static library if the executable also links with a shared library which in turn has (in part) the same object code as the static library. That is the shared library and the static library have overlap in terms of object code. Using this option would force all symbols(regardless of use) to be resolved in the executable. This is supposed to avoid object code duplication. This is confusing, if a symbol is refereed in the program it must be resolved uniquely at link time, what is this business about duplication ? (Forgive me if this paragraph is not quite the epitome of clarity)

Thanks 

ld linker question: the --whole-archive option

I&#39;m getting into CMAKE usage with C and actually I&#39;m creating two very small static libraries.

My goal is:

 1. The libraries are compiled and linked into *.a files. [THIS
    WORKS]
 2. Then I wish to copy that *.a files into /usr/local/lib [THIS ALSO WORKS]
 3. As far as I know about libraries (very little), they are linked using `-lnameoflib`, which is a compiler flag. OK. I have prepared my CMakeLists.txt and it actually copies *.a files into `/usr/local/lib`. However, to be able to use them in a program, I also need to copy their header files into `/usr/local/include`, then I can include them the easy way `#include &lt;mylibheader.h&gt;`. That&#39;s how I understand it now.

And my question is - how is the proper way of copying header files into /usr/include folder with CMAKE? I would like it to copy them automatically when `make install` is executed, like *.a files are.

For both of the libraries I have a smiliar CMakeLists.txt:

    project(programming-network)
    
    add_library(programming-network STATIC
        send_string.c
        recv_line.c
        )
        
    INSTALL(TARGETS programming-network
            DESTINATION &quot;lib&quot;
            )

CMAKE - How to properly copy static library&#39;s header file into /usr/include?

I&#39;m trying to link to a static library on OS X. I used the `-static` flag in the gcc command but I get the following error message:

&lt;pre&gt;
ld_classic: can&#39;t locate file for: -lcrt0.o
collect2: ld returned 1 exit status
&lt;/pre&gt;

I looked in the man pages and it reads something like: 

&gt; This option will not work on Mac OS X unless all libraries (including libgcc.a) have also been compiled with -static. Since neither a static version of libSystem.dylib nor crt0.o  are provided, this option is not useful to most people.


Is there another way to link to this static library?

How to static link on OS X

I know `.o` are object files, `.a` are static libraries and `.so` are dynamic libraries? What is their physical significance? When can I use some and when not?

All Static Libraries Solutions on Gang of Coders

Total of 37 Static Libraries Solutions