PerlEmbed - C# - Mono - Linux

c#, embed, linux, mono, perl

Solution

Got it to work!

Made the perl program, showtime.pl:

#/usr/bin/perl

sub showtime {
    print "WOOT!\n";
}

Made the c program, perlembed.c:

#include <EXTERN.h>
#include <perl.h>

static PerlInterpreter *my_perl;

void Initialize(char* processName, char* perlFile)
{
    int argc = 2;
    char *argv[] = { processName, perlFile },
        *env[]  = { "" };

    PERL_SYS_INIT3(&argc, &argv, &env);
    my_perl = perl_alloc();
    perl_construct(my_perl);
    perl_parse(my_perl, NULL, argc, argv, NULL);
    PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
}

void Call(char* subName)
{
    char *args[] = { NULL };
    call_argv(subName, G_DISCARD | G_NOARGS, args);
}

void Dispose()
{
    if (my_perl != NULL)
    {
      perl_destruct(my_perl);
      perl_free(my_perl);
      PERL_SYS_TERM();
      my_perl = NULL;
    }
}

Compiled it via:

"gcc -shared -Wl,-soname,perlembed.so -o perlembed.so perlembed.c `perl -MExtUtils::Embed -e ccopts -e ldopts`"

Made this C# program, perlembed.cs:

using System;
using System.Runtime.InteropServices;

public class Woot
{
  [DllImport("perlembed.so", SetLastError = true)]
  public static extern void Initialize(string processName, string perlFile);

  [DllImport("perlembed.so", SetLastError = true)]
  public static extern void Call(string subName);

  [DllImport("perlembed.so", SetLastError = true)]
  public static extern void Dispose();

    static void Main()
    {
        Console.WriteLine("Starting up C#...");

        try
        {
            Initialize("perlembed.exe", "showtime.pl");

            Call("showtime");
        }
        catch(Exception exc)
        {
            Console.WriteLine(exc.ToString());
        }
        finally
        {
            Dispose();
        }

        Console.WriteLine("DONE!...");
    }
}

Compiled it with gmcs, and got the output:

Starting up C#...
WOOT!
DONE!...

Hope this helps anyone out there, can't believe it took 3 languages to happen. I will move on to passing scalars, arrays, etc. but it should be a breeze from here.

Problem

Has anyone attempted using perlembed in Mono on Linux? Here is the link: perlembed Here is my first attempt at the DllImport signatures: ``` private const string PERL_LIB = "/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so"; [DllImport(PERL_LIB, EntryPoint = "perl_alloc", SetLastError = true)] public static extern IntPtr Alloc(); [DllImport(PERL_LIB, EntryPoint = "perl_construct", SetLastError = true)] public static extern void Construct(IntPtr hPerl); [DllImport(PERL_LIB, EntryPoint = "perl_destruct", SetLastError = true)] public static extern void Destruct(IntPtr hPerl); [DllImport(PERL_LIB, EntryPoint = "perl_free", SetLastError = true)] public static extern void Free(IntPtr hPerl); [DllImport(PERL_LIB, EntryPoint = "perl_parse", SetLastError = true)] public static extern void Parse(IntPtr hPerl, IntPtr @null, int argc, StringBuilder argv, StringBuilder env); [DllImport(PERL_LIB, EntryPoint = "perl_run", SetLastError = true)] public static extern void Run(IntPtr hPerl); [DllImport(PERL_LIB, EntryPoint = "eval_pv", SetLastError = true)] public static extern void Eval(string expr, bool flag); ``` The CORE directory can change per Linux distro. The following code runs, but crashes on the `Parse()` method: ``` try { Console.WriteLine("Alloc"); IntPtr perl = Alloc(); Console.WriteLine("Construct"); Construct(perl); Console.WriteLine("Parse"); Parse(perl, IntPtr.Zero, 3, new StringBuilder("-e 0"), new StringBuilder()); Console.WriteLine("Run"); Run(perl); Console.WriteLine("Eval"); Eval("$a = 3.14; $a **= 2", true); Console.WriteLine("Destruct"); Destruct(perl); Console.WriteLine("Free"); Free(perl); } catch (Exception exc) { Console.WriteLine(exc.ToString()); } ``` My crash reads: ``` ================================================================= Got a SIGSEGV while executing native code. This usually indicates a fatal error in the mono runtime or one of the native libraries used by your application. ================================================================= Stacktrace: in (wrapper managed-to-native) Woot:Parse (intptr,intptr,int,System.Text.StringBuilder,System.Text.StringBuilder) <0x4> in (wrapper managed-to-native) Woot:Parse (intptr,intptr,int,System.Text.StringBuilder,System.Text.StringBuilder) <0xffff9f85> in Woot:Main () <0x8d> in (wrapper runtime-invoke) System.Object:runtime_invoke_void (object,intptr,intptr,intptr) <0x7c79b09> ``` Native stacktrace: ``` mono(mono_handle_native_sigsegv+0xbb) [0x81368fb] mono [0x8105670] [0x4c45a440] /usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so(perl_parse+0xa3) [0x4c6e6e93] [0x43ad78] [0x434cae] [0x434abe] mono(mono_runtime_exec_main+0x62) [0x80ae5a2] mono(mono_runtime_run_main+0x152) [0x80af6e2] mono(mono_main+0xef9) [0x805dae9] mono [0x805c702] /lib/libc.so.6(__libc_start_main+0xdc) [0x4c48d724] mono [0x805c651] ``` There are some `PERL_SYS_INIT3`, and `PERL_SYS_TERM` calls that perlembed mentions, but I have not been able to call those methods through `DllImport`. I always get `EntryPointNotFoundException` in those cases. I'm sure they are in a different file I need to import. Can someone direct me in the correct way to call `DllImports` to perlembed?

Original source