https://github.com/flowerwrong/ffi-demos
ruby ffi bind c demos
https://github.com/flowerwrong/ffi-demos
Last synced: 3 months ago
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ruby ffi bind c demos
- Host: GitHub
- URL: https://github.com/flowerwrong/ffi-demos
- Owner: FlowerWrong
- Created: 2015-12-08T03:02:18.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2015-12-10T08:12:33.000Z (over 9 years ago)
- Last Synced: 2025-01-11T11:16:16.313Z (5 months ago)
- Language: C
- Size: 2.93 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
## ruby ffi example
#### What is ffi?
A foreign function interface (FFI) is a mechanism by which a program written in one programming language can call routines or make use of services written in another. See more [here](https://en.wikipedia.org/wiki/Foreign_function_interface)
#### Generate .so shared lib
```c
// cal.h
int sum(int a, int b);
// cal.c
#include "cal.h"
int sum(int a, int b) {
return a + b;
}
```
```bash
gcc -fPIC -shared -o libcal.so cal.c
sudo mv cal.h /usr/local/include
sudo mv libcal.so /usr/local/lib
sudo chmod 0755 /usr/local/lib/libcal.so
sudo ldconfig
ldconfig -p | grep cal
```
#### Test it in main function
```c
// main.c
#include
#include "cal.h"
int main(int argc, char const *argv[]) {
int total;
total = sum(1, 4);
printf("sum is %d\n", total);
return 0;
}
```
```bash
gcc -Wall -o main main.c -I/usr/local/include -L/usr/local/lib -lcal
ldd main
./main
```
#### Ruby ffi
```bash
gem install ffi
```
```ruby
require 'ffi'
module MyCal
extend FFI::Library
ffi_lib 'c' # use libc
attach_function :puts, [:string], :int # puts function is from libc
ffi_lib 'cal' # use libcal write by myself
attach_function :sum, [:int, :int], :int # sum function is from libcal
end
MyCal.puts 'I am using libcal write by myself.'
total = MyCal.sum(1, 3)
p "sum 1 and 3 is #{total}"
```
```bash
ruby cal.rb # => "sum 1 and 3 is 4"
```
#### Todo
- [ ] [write a http-parser ffi](https://github.com/nodejs/http-parser)
#### Reference
* [shared-libraries-linux-gcc](http://www.cprogramming.com/tutorial/shared-libraries-linux-gcc.html)
* [what is ffi?](https://en.wikipedia.org/wiki/Foreign_function_interface)
* [ruby-ffi wiki](https://github.com/ffi/ffi/wiki)