You're very close, the only thing missing is a tiny bit of C linking
experience. I dropped the `.h` file and the `.so` (Linux's version of a `.dll`)
in the same folder as this Nim file:
import futhark
import strutils
# Tell futhark where to find the C libraries you will compile with, and what
# header files you wish to import.
importc:
path "."
"cozo_c.h"
{.passL: "-L. -lcozo_c".}
proc query(db_id: int32, query: cstring) =
let empty_params = "{}"
var res: cstring
res = cozo_run_query(db_id, query, empty_params, false)
echo $res
cozo_free_str(res)
proc main() =
var db_id: int32
var err: cstring
err = cozo_open_db("mem", "", "{}", addr db_id)
if err != nil :
echo $err
cozo_free_str(err)
return
query(db_id, "?[] <- [[1, 2, 3]]")
echo cozo_close_db(db_id)
main()
Run
Then it's a simple `nim c <ourfile>.nim` to build the binary. Now this is
dynamically linked to `libcozo_c.so`, but running it will throw an error (on
Linux, on Windows you're fine since the library is in the same folder). We need
to tell it to look for the dynamic library in the local folder and not just in
the system folders: `LD_LIBRARY_PATH=. ./<ourfile>`. And there you go, a
dynamically linked library which runs fine.
Of course you could clean it up a little bit while we're at it:
import futhark
import strutils
# Tell futhark where to find the C libraries you will compile with, and what
# header files you wish to import.
proc renameCallback(name, kind: string, partOf = ""): string =
result = name
result.removePrefix("cozo_")
importc:
renameCallback renameCallback
path "."
"cozo_c.h"
{.passL: "-L. -lcozo_c".}
proc query(dbId: cint, query: cstring) =
let
emptyParams = "{}"
res = dbId.runQuery(query, emptyParams, false)
echo $res
freeStr(res)
var
dbId: cint
err = openDb("mem", "", "{}", addr dbId)
if err != nil:
echo $err
freeStr(err)
quit 1
dbId.query("?[] <- [[1, 2, 3]]")
echo dbId.closeDb
Run
