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@Overdrivr
Last active August 8, 2023 22:58
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Pass and return structs (by copy) between C and Python using CFFI
from cffi import FFI
ffi = FFI()
ffi.cdef("""
typedef struct T T;
struct T
{
int a;
float b;
};
void pass_a_struct(T somedata);
T get_a_struct();
"""
)
# Compile the C sources to produce the following .dll (or .so under *nix)
lib = ffi.dlopen("somelib.dll")
# Create a new C struct of type T
fooStruct = ffi.new("struct T *")
# Using struct fields defined in C code is as simple as this
fooStruct.a = 12;
fooStruct.b = 3.5;
# To pass the struct you need to dereference it (like you would in C)
lib.pass_a_struct(fooStruct[0])
# To get the struct use simple assignement
fooStruct = lib.get_a_struct()
# And that's it
print("Got : ",fooStruct)
print("T.a",fooStruct.a)
print("T.b",fooStruct.b)
#include "somelib.h"
static T myStruct;
void pass_a_struct(T somedata)
{
myStruct.a = somedata.a * 2;
myStruct.b = somedata.b / 3.f;
}
T get_a_struct()
{
return myStruct;
}
#ifndef SOMELIB_H_
#define SOMELIB_H_
typedef struct T T;
struct T
{
int a;
float b;
};
// pass a struct
void pass_a_struct(T somedata);
// get back a struct
T get_a_struct();
#endif
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