Nifty - Erlang NIF Wrapper Generator

Nifty is an interface generator that allows the use of C modules from Erlang.

Web page: [http://parapluu.github.io/nifty/]

A Simple Example

Let's say we have two C files mylib.h and mylib.c which we want to use in our Erlang application:

/* mylib.h */
extern int fib(int n);

/* mylib.c */
int
fib(int n) {
  if (n <= 2) {
    return 1;
  } else {
    return fib(n-1) + fib(n-2);
  }
}

We can generate a NIF interface and use it from Erlang with the following command:

nifty:compile("mylib.h", mylib, nifty_utils:add_sources(["mylib.c"], [])).
5 = mylib:fib(5).

nifty:compile/3 gets as its first argument a header or interface file and tries to generate an interface for all specified functions. The second argument specifies the Erlang module the interface is about to use and the third argument is used for additional options. These options are compatible with the ones rebar uses to compile NIF modules. In fact, Nifty uses rebar to compile the generated interface.

Installation

After successfully cloning enter the following commands

make

and include Nifty in your ERL_LIBS path.

Unit Tests

Run the following command to check that everything works correct:

make tests

Dependencies

• The clang compiler and libclang, including the header files.
• [Optional] PropEr for the unit tests.

Base Types

C Types	Erlang Types	Nifty Type Name
signed int or int	integer()	nifty.int
unsigned int	integer()	nifty.unsigned int
char	integer()	nifty.char
short	integer()	nifty.short
long	integer()	nifty.long
long long	integer()	nifty.long long
float	float()	nifty.float
double	float()	nifty.double
<type> *	{integer(), string()}	<module>.<type> *

Known Limitations

• Function pointers are only partially supported.
• There is no support for anonymous structs and unions.
• Functions using unsupported types are not translated and a warning is issued.
• Functions with a variable number of arguments (va_list or ...) are not supported. If va_list as type is used, Nifty will print a warning. If ... is used, then the function is translated without the variable arguments: int printf(const char *format, ...) will be translated into printf/1.
• The usage of incomplete types is limited.
• Nifty has not been tested under Windows.