I have written a C++ library with a C wrapper and want to call those functions from my Rust project. However, when I try to link my Rust project to the C library, I get a long error with the note
note: /usr/bin/ld: cannot find -l../cpp_library/build/libdisplay.so
I have tried passing an absolute path to the library and received a similar error.
My combined project has the following directory and contents
├── cpp_library
│ ├── CMakeLists.txt
│ ├── include
│ │ └── display.h
│ └── src
│ ├── display.cpp
│ └── main.cpp
└── rust_project
├── build.rs
├── Cargo.lock
├── Cargo.toml
├── src
└── main.rs
CMakeLists.txt
cmake_minimum_required(VERSION 3.1.0)
project(directory_test)
set(CMAKE_BUILD_TYPE Release)
#Bring the headers into the project
include_directories(include)
set(SOURCES "src/display.cpp")
#Generate the shared library from the sources
add_library(display SHARED ${SOURCES})
add_executable(display_test "src/main.cpp" ${SOURCES})
display.h
extern "C" {
void display();
}
display.cpp
#include <iostream>
#include "display.h"
void display(){
std::cout << "A C++ println" << std::endl;
}
main.cpp
#include "display.h"
int main() {
display();
}
build.rs
fn main() {
println!("cargo:rustc-link-search=../cpp_library/build/");
println!("cargo:rustc-link-lib=../cpp_library/build/libdisplay.so");
}
main.rs
extern {
fn display();
}
fn main() {
println!("Hello, world!");
unsafe {
display();
}
}
You can also see the project on Github.
I build the C library with
cd cpp_library
mkdir build
cd build
cmake ..
make
When I build the Rust project, I get the error shown above.
How am I supposed to link the C library to the Rust project?
Update 1
The posts How do I specify the linker path in Rust? and Where should I place a static library so I can link it with a Rust program? indicate how to add a directory to the library search path and link a library. I have tried these solutions, but still receive the error mentioned above.
Following the advice of Linking Rust application with a dynamic library not in the runtime linker search path, I compiled the rust project with
cargo rustc -- -C link-args='-Wl,-rpath,$ORIGIN/../../../cpp_library/build/'
but received the same error. I also tried passing an absolute path and received the same result.
I removed the redundant #[link(name = "display")], but this did not resolve the problem.
