Ошибка добавления символов dso missing from command line

The DSO missing from command line error happens when developers mention and include the specific library before the object. Therefore, the system displays an error message with different forms, but developers usually see the following statement: libz error adding symbols: DSO missing from command line CMake error.

As a result, our team wrote this extended article that includes several examples, solutions methods, and valuable tips on removing the DSO missing from command line ROS bug.

So, you will effortlessly remove this annoying mistake from your system when you finish reading all DSO missing from command line G++ chapters.

What Causes the Common DSO Missing From Command Line Error?

The DSO missing from the command line is caused when programmers and developers introduce and mention the specific library before the object. As a result, the system cannot initiate the intended command because the entity does not have a library for the data.

Unfortunately, this is not the only common culprit because this error can appear when developers fail to include a library in the compilation steps. Although this depends on the distribution’s version and compiler, it can occur when developers expect the least.

In addition, the command line error has different forms, so less experienced programmers should not worry if the entire error message differs from our example. We will show you three models that display the same error with different programs and versions.

For instance, the error may appear with the following structure:

libtbb so 2 error adding symbols: dso missing from command line

As you can tell, the final code line includes the generic mistake, but the beginning explains more about the version and possible causes. However, this bug can affect other versions and programs, as confirmed by the following example:

libc.so.6: error adding symbols: dso missing from command line

The system displays mistakes due to inadequate libraries or values, although developers may use different programs and elements.

Lastly, this error can have another form, as shown in the following message:

libgobject.0.so.0: error adding symbols: dso missing from command line

All error messages are common, but the actual bug can differ based on your script.

– Compiling Functions Causes a Mistake

The same error can appear when programmers compile several functions in a single script. For instance, they can include the commands and locations inside the element, but the system will display the mistake unless all values are correct.

Therefore, our experts suggest double-checking the script for compiling function errors that can ruin your programming experience. We will show you an example that specifies several locations, but be aware this may vary from your syntax.

Please look at the following example that compiles several functions:

As you can tell, the declarations appear correct and fully functional, but the program displays the error.

This happens when developers include the library before the objects and locations, as explained in the previous chapter. We will show you another example before explaining the debugging methods and solutions.

– Creating a Download Tar From a Home Page

Developers and programmers will experience the same error when creating a download tar from a home page. Tarring files from home pages requires following the instructions explicitly because the system must download the correct compiled data. However, an error might appear at some point when developers use J8 or J9 on Linux operating systems.

The following example captures the error when creating a download tar:

This is the error developers will see when downloading the tar from a home page. However, the solutions are simple, as explained in the following chapters.

Fix the DSO Missing From Command Line Error: Several Solutions

You can fix the DSO error by mentioning the command line after the object files that developers compile to remove the error message. Beginners may need help locating the command line quickly. Introducing -lpthread option to the compiler is also used to fix this error.

Fortunately, our experts provide several examples that debug the error without affecting other primary and secondary functions. For instance, we will show you a script that fixes this article’s first error.

Refer to the following syntax to learn how to mention the command line after the object:

Programmers can copy and paste this script into their documents to debug the error, although they might need to change several values and tags.

Still, the command line appears after the object, a minor change that debugs the syntax and its functions. In addition, this article provides another solution for the same error.

– Introducing the -Lpthread Option

Another standard solution for the same error is introducing the -lpthread option to the compiler. This debugs the mistake because the command has a new link used by the system to locate the missing command line.

Although your values and commands will differ, we suggest introducing the -lpthread option above the original location.

Doing this is not complicated, as confirmed in the next example:

We kept the syntax short to help less experienced developers quickly follow the changes. Therefore, we are confident you will overcome all obstacles for the missing command line error.

Conclusion

Debugging annoying mistakes in your document is sometimes challenging, as confirmed by the missing command line error. However, our experts explained several terms summarized in the following bullet list:

• The missing command line error usually appears when developers and programmers mention the library before the object
• The same command line error has several forms and locations with similar elements and tags
• Our experts suggest introducing the library after the object to debug your script and its functions
• Programmers can use alternative solutions to fix the mistake by including a backup option
• Our experts suggest double-checking your syntax before writing the commands because you can ruin other elements

The command line error can affect all operating systems and versions because developers use the same command. However, you no longer have to worry because by following this profound guide, you can get rid of this error message efficiently.

Coding has become far simpler these days as compared to what it used to be with languages like C and even Assembly requiring programmers to put in a lot of time and study to get up to speed. However, as easy as programming has become with modern languages, there are still random bugs and glitches that keep popping up from time to time. 

In this article, we’re talking about the “error adding symbols: DSO missing from command line” issue, the reasons behind it and what you can do to fix the problem. 

Also read: Fix: Panic: Runtime error: Invalid memory address or nil pointer dereference

The issue generally occurs when the linker can’t find the required symbol with its normal search but the symbol is otherwise available in one or more dependencies of a mentioned dynamic library.  This means that mentioning a specific library before the object doesn’t allow the system to initiate the intended command as the entity doesn’t have a library for the data. 

Other common causes include:

• Syntax issues or other bugs in code
• Library isn’t included in compilation steps

How to fix the error adding symbols: DSO missing from command line issue?

Based on whether you’re a maintainer or just trying to compile or run the software, there are different approaches to the problem.

If you’re a software maintainer

Really the only thing you can do in such scenarios is to ensure that all libraries required to successfully compile the program are directly specified in the linker command line or are bundled with the package otherwise. Do keep in mind that the order in which the libraries are mentioned can also matter here. 

If you’re trying to compile or run a program

If you’re just trying to compile or run a program, the first step is checking the program dependencies and making sure that you have the compilation environment set up properly. Once again, the order in which the libraries are mentioned can also come into play here so you might have to experiment with different orders based on when you’re referencing the library in your code. 

Another common way of injecting this into a build is to either use lpthreads or ldflags before building the program as follows. 

export LDFLAGS="-Wl,--copy-dt-needed-entries"

The aforementioned command can allow for a more permissive view of what symbols or libraries are available to the compiler and hence avoid the issue. 

Also read: Fix: Unknown error: soap-error: encoding: object has no uirequestid property

Back when I was coding in C, I found a very strange problem: the ld library has been linked in the plug-in loader, but when the application is linked to the plug-in loader, it still needs to link ld explicitly. Otherwise, it will report: DSO missing from command line. It means the dynamic library is not specified on the command line.

/usr/bin/ld: /tmp/ccDQXTKy.o: undefined reference to symbol '_Z5funB2v'
.//libB.so: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit statusCode language: JavaScript (javascript)

The DSO missing from command line message will be shown when the linker can’t find the required symbol with its normal search, but the symbol is available in one of the dependencies of a directly specified dynamic library.

In the past, the linker thought that symbols in languages that depended on other languages were available. But in a later version, that changed, and now the linker has a stricter view of what is available. So, the message is meant to help with this change.

Reproduce the error

Let’s take a look at an example: When linking an executable file, it depends on libA.so, and libA.so depends on libB.so, and the function in libB.so is directly called in the executable file, then the link An error will occur.

libA.so is explicitly linked to libB.so during the compilation process. The executable file uses the function of libB.so, binuntils version ≥ 2.22.

Not much to say , let’s take a look at the code that can reproduce the problem

Below is the source code of libB.so:

#include <stdio.h>

int funB1(){

    printf("in funB1");

    return 0;
}
libB.so
int funB2(){

    printf("in funB2");

    return 0;
}Code language: PHP (php)

There are two functions: funB1 and funB2.
The funB1 function will be called by libA, and the funB2 will be called by the executable file.

Now we compile libB.so:

gcc libB.cpp -fPIC -shared -o libB.soCode language: CSS (css)

Below is the source code of libA.so:

#include <stdio.h>

int funB1();

int funA1(){

    printf("in funA1 \n");

    funB1();

    return 0;
}Code language: PHP (php)

There is only one function funA1 in this library, which calls funB1 function in libB. And this function will then be called by the executable file.

Compile libA.so:

$ gcc libA.cpp -fPIC -shared -o libA.so -Wl,-rpath=./ -L./ -lB

Below is the source code of main.cpp:

int funA1();
int funB2();

int main(){

    funA1();
    funB2();

    return 0;
}Code language: JavaScript (javascript)

Compile main.cpp: (compilation method to reproduce the error)

gcc main.cpp -L./ -lA

When we compiled main.cpp using gcc main.cpp -L./ -lA, the DSO missing from command line error will be printed out.

/usr/bin/ld: /tmp/ccDQXTKy.o: undefined reference to symbol '_Z5funB2v'
.//libB.so: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit statusCode language: JavaScript (javascript)

Let’s use the following command to see if libA.so specify to use libB.so.

$ ldd libA.so

The output contains some useful information:

    linux-vdso.so.1 =>  (0x00007ffd09def000)
    libB.so => ./libB.so (0x00007fc513d7d000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fc5139b3000)
    /lib64/ld-linux-x86-64.so.2 (0x00007fc514181000)Code language: PHP (php)

Obviously libA.so has explicitly indicated that I want to rely on libB.so, so why did libA.so be linked when compiling main.cpp, but GCC also asked us to explicitly link libB.so?

The answer is simple, that is, GCC just wants you to link it explicitly.

Since binutils version 2.22, if you use functions in the dynamic library that you depend on, you must also explicitly specify the dynamic library on which the dynamic library you depend depends on.

In fact, this is binutils after version 2.22, with the --no-copy-dt-needed-entries option turned on by default. When this option is enabled, the compiler will not recursively fetch dependencies that depend on dynamic libraries when linking, so the above problem occurs.

Below is the help message on --no-copy-dt-needed-entries:

   --copy-dt-needed-entries
   --no-copy-dt-needed-entries
       This option affects the treatment of dynamic libraries referred to by DT_NEEDED tags inside ELF dynamic libraries mentioned on the command line.  Normally the linker won't add a DT_NEEDED
       tag to the output binary for each library mentioned in a DT_NEEDED tag in an input dynamic library.  With --copy-dt-needed-entries specified on the command line however any dynamic
       libraries that follow it will have their DT_NEEDED entries added.  The default behaviour can be restored with --no-copy-dt-needed-entries.

       This option also has an effect on the resolution of symbols in dynamic libraries.  With --copy-dt-needed-entries dynamic libraries mentioned on the command line will be recursively
       searched, following their DT_NEEDED tags to other libraries, in order to resolve symbols required by the output binary.  With the default setting however the searching of dynamic
       libraries that follow it will stop with the dynamic library itself.  No DT_NEEDED links will be traversed to resolve symbols.

This roughly means that libraries that follow --no-copy-dt-needed-entries do not traverse their dependencies, and the opposite is true for --no-copy-dt-needed-entries. That is, using the following command to compile the main.cpp can avoid this problem.

$ gcc main.cpp -L./ -Wl,--copy-dt-needed-entries -lA

Alternatively, you can use the option -Wl,--copy-dt-needed-entries to allow a more permissive view of symbols.

Common ways to inject this into a build are to export LDFLAGS before running configure:

export LDFLAGS="-Wl,--copy-dt-needed-entries"Code language: JavaScript (javascript)

We hope that the information above is useful and helped you successfully fix the DSO missing from command line error message.

We’ve also written a few other guides on C programming, such as unistd.h on Windows and How to automatically indent your code in Visual Studio Code.

If you have any questions, then please feel free to ask in the comments below.