Why Can't My Linker Find `-l`?

"usr/bin/ld: cannot find -l" Troubleshooting Guide

When compiling a program, encountering the error "usr/bin/ld: cannot find -l" indicates that the linker is unable to locate the specified library. To resolve this issue, employ the following troubleshooting steps:

1. Verify Library Existence:

Ensure that the library you are referencing exists in the specified location. Run the following command to list all available libraries:

ldconfig -p | grep <nameOfTheLibrary>

2. Symbolic Link Validation:

If you have created a symbolic link to the library, confirm that it is correct and points to the actual library file. Use the "ls -l" command to view the link:

ls -l <symbolicLink>

3. Verbose Linker Output:

To determine the specific files the linker is searching for, run it in verbose mode. Append the "--verbose" flag to the linking command:

ld -l<nameOfTheLibrary> --verbose

The output will show all potential directories and files that the linker is considering.

4. Install Missing Libraries:

If the library does not exist or cannot be located, install it using your package manager. For example, on a Debian-based system:

sudo apt-get install <nameOfTheLibrary>-dev

5. Add Library Path to Command:

In some cases, the linker may not be able to find the library automatically. You can manually specify the library path using the "-L" flag:

g++ -o myprogram myprogram.cpp -l<nameOfTheLibrary> -L/path/to/library

Example:

To resolve the issue described in the referenced problem, where the linker could not find the ZLIB library:

1. Ensure that the zlib.so file exists in the specified directory or create a symlink to the versioned file (zlib.so.N).
2. Run ld -lzlib --verbose to verify the files being searched for.
3. If zlib.so is missing, create a symlink to the existing versioned file:

sudo ln -s /usr/lib/libz.so.1.2.8 /usr/lib/libzlib.so

The above is the detailed content of Why Can't My Linker Find `-l`?. For more information, please follow other related articles on the PHP Chinese website!