Add an example on how to use it

This commit is contained in:
PMunch 2018-07-06 10:26:45 +02:00
commit 18f0549ab2
2 changed files with 58 additions and 0 deletions

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examples/loader.nim Normal file
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# Compile with: nim c --passL:-rdynamic -r loader.nim
import os
import dynlib
import libffi
when defined(linux):
proc dlerror(): cstring {.importc.}
else:
proc dlerror(): string = "Unknown error"
echo "Trying to load the library at: " & $(getAppDir() / "libplugin.so")
# First let's load a library to find procedures in
var dll = loadLib($(getAppDir() / "libplugin.so"), false)
if dll == nil:
echo "Something went wrong with loading the plugin:\n" & $dlerror()
quit 1
# Now let's try and get a symbol from it
var procSym = dll.symAddr("hello")
# We need to set up our call first. This procedure takes one int argument
var
cif: Tcif
params: ParamList
# The argument the procedure takes
params[0] = type_sint64.addr
# Prepare the call, with the aforementioned params, and no return type
if OK != prep_cif(cif, DEFAULT_ABI, 1, type_void.addr, params):
echo "Something went wrong with preparing the statement"
quit 1
# Now let's set up a list of arguments
var args: ArgList
var i = 100
args[0] = i.addr
# And call the symbol with our argument
call(cif, procSym, nil, args)
# Let's do another one. This time without arguments, but with a return type
if OK != prep_cif(cif, DEFAULT_ABI, 0, type_sint64.addr, params):
echo "Something went wrong with preparing the statement"
quit 1
# Again load the symbol
var highFiveSym = dll.symAddr("highFive")
# Set up the position of our return value and call the procedure
var theFive = 0
call(cif, highFiveSym, theFive.addr, args)
echo theFive

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examples/plugin.nim Normal file
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# Compile with: nim c --noMain --app:lib plugin.nim
proc hello(x: int) {.exportc.} =
echo "Hello world, ", x
proc highFive(): int {.exportc.} =
result = 5
echo "Here you go!"