What is /usr/bin/ld: cannot find -lcudart and How to Fix It?

Reasons behind /usr/bin/ld: cannot find -lcudart

There can be several reasons why the linker is unable to find the cudart library. Some of the most common reasons are:

1. Incorrect CUDA installation

The cudart library is a part of the CUDA toolkit, which is required to compile and run CUDA applications. If the CUDA toolkit is not installed properly or is not installed at all, the cudart library will not be available to the linker, and you will see the error message /usr/bin/ld: cannot find -lcudart.

2. Incorrect library path

The linker looks for libraries in the directories specified by the LD_LIBRARY_PATH environment variable. If the cudart library is installed in a directory that is not included in the LD_LIBRARY_PATH variable, the linker will not be able to find it, and you will see the error message /usr/bin/ld: cannot find -lcudart.

3. Incorrect library name

The cudart library is named libcudart.so on Linux systems and cudart.dll on Windows systems. If the library is named differently or if the linker is looking for a different version of the library, you will see the error message /usr/bin/ld: cannot find -lcudart.

Solutions to fix /usr/bin/ld: cannot find -lcudart

Now that we know the reasons behind the error message, let’s discuss the solutions to fix it.

1. Check CUDA installation

The first step is to check if the CUDA toolkit is installed properly. You can do this by running the command nvcc --version in the terminal. If the command is not found, it means that the CUDA toolkit is not installed. If the output shows the version number of the CUDA toolkit, it means that the toolkit is installed. If the toolkit is installed, make sure that it is the correct version for your system.

2. Check library path

If the CUDA toolkit is installed properly, the next step is to check the library path. You can do this by running the command echo $LD_LIBRARY_PATH in the terminal. This command will show the directories where the linker looks for libraries. Make sure that the directory where the cudart library is installed is included in the LD_LIBRARY_PATH variable. If the directory is not included, you can add it by running the command export LD_LIBRARY_PATH=/path/to/cudart:$LD_LIBRARY_PATH. Replace /path/to/cudart with the actual path where the cudart library is installed.

3. Check library name

If the CUDA toolkit is installed properly and the library path is correct, the next step is to check the library name. Make sure that the library is named libcudart.so on Linux systems and cudart.dll on Windows systems. If the library is named differently or if the linker is looking for a different version of the library, you can create a symbolic link to the correct library name. For example, if the linker is looking for libcudart.so.8.0 and the actual library name is libcudart.so.10.0, you can create a symbolic link by running the command ln -s /path/to/libcudart.so.10.0 /path/to/libcudart.so.8.0.

Conclusion

In this blog post, we discussed the reasons behind the error message /usr/bin/ld: cannot find -lcudart and provided solutions to fix it. We hope that this article has been helpful in resolving this issue for you. If you have any questions or comments, please feel free to leave them below.

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