Re: [Help-glpk] some example C# code that call GLPK in C# from visual studio 2013

[Heinrich Schuchardt]

Hello Nigel,

GLPK does not call SetLastError. So why do you want it in the declaration?

I guess you want to remove unsafe because no pointer to a C# object is passed 
to GLPK?

Best regards

Heinrich Schuchardt

Am 13.04.15 um 13:15 schrieb Nigel Galloway

> Looking at the example in the wiki, in C# 5 the following works fine:
> 
> 
> 
> using System;
> 
> using System.Runtime.InteropServices;
> 
> 
> 
> 
> 
> class test {
> 
>     [DllImport("glpk.dll", SetLastError = true)]
> 
>     static extern IntPtr glp_version();
> 
> 
> 
>     public static void Main(string[] args) {
> 
>         Console.WriteLine("Version is {0}",
> 
>         Marshal.PtrToStringAnsi(glp_version()));
> 
>     }
> 
> }
> 
> 
> 
> producing:
> 
> 
> 
>  Version is 4.55.
> 
> 
> 
> This is safe and does not require to be compiled with the unsafe flag.
> 
> In t1.cs the part that makes it unsafe is the use of fixed to define ia
> 
> ar and ja. In C# 5 these can be marshalled with UnmanagedType.LPArray.
> 
> Most of the straight forward interface to glpk can be linked safely. The
> 
> main problem arises when you have to obtain a structure defined in C
> 
> from glpk which you have to modify in C# and return to glpk.
> 
> 
> 
> -- 
> 
>   Nigel Galloway
> 
>   address@hidden
> 
> 
> 
> On Tue, Apr 7, 2015, at 05:10 AM, Heinrich Schuchardt wrote:
> 
> > Hello Nigel,
> 
> > 
> 
> > how would you call native dlls in C# 5?
> 
> > Is this supported in Mono, too?
> 
> > 
> 
> > Best regards
> 
> > 
> 
> > Heinrich Schuchardt
> 
> > 
> 
> > 
> 
> > Am 07.04.15 um 13:30 schrieb Nigel Galloway
> 
> > 
> 
> > > There is also an example in glpk's example directory. But this and the
> 
> > > 
> 
> > > wiki are very old examples (C# 2.0 I think). This is not how to do it
> 
> > > 
> 
> > > with C# 4 or 5.
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > -- 
> 
> > > 
> 
> > >   Nigel Galloway
> 
> > > 
> 
> > >   address@hidden
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > On Wed, Apr 1, 2015, at 10:50 AM, Heinrich Schuchardt wrote:
> 
> > > 
> 
> > > > Please, see http://en.wikibooks.org/wiki/GLPK/C-Sharp
> 
> > > 
> 
> > > > and read
> 
> > > 
> 
> > > > https://msdn.microsoft.com/en-us/library/26thfadc%28v=vs.110%29.aspx
> 
> > > 
> 
> > > > (Consuming Unmanaged DLL Functions)
> 
> > > 
> 
> > > > 
> 
> > > 
> 
> > > > Best regards
> 
> > > 
> 
> > > > 
> 
> > > 
> 
> > > > Heinrich Schuchardt
> 
> > > 
> 
> > > > 
> 
> > > 
> 
> > > > On 01.04.2015 17:50, usa usa wrote:
> 
> > > 
> 
> > > > > Hi,
> 
> > > 
> 
> > > > > 
> 
> > > 
> 
> > > > > Could anybody recommand some example C# code that call GLPK in C# from
> 
> > > 
> 
> > > > > visual studio 2013 on win 7 ?
> 
> > > 
> 
> > > > > 
> 
> > > 
> 
> > > > > I am new to use GLPK from C#.
> 
> > > 
> 
> > > > > 
> 
> > > 
> 
> > > > > Any help would be appreciated.
> 
> > > 
> 
> > > > > 
> 
> > > 
> 
> > > > > thanks
> 
> > > 
> 
> > > > 
> 
> > > 
> 
> > > > 
> 
> > > 
> 
> > > > _______________________________________________
> 
> > > 
> 
> > > > Help-glpk mailing list
> 
> > > 
> 
> > > > address@hidden
> 
> > > 
> 
> > > > https://lists.gnu.org/mailman/listinfo/help-glpk
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > -- 
> 
> > > 
> 
> > > http://www.fastmail.com - IMAP accessible web-mail
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > 
> 
> > > _______________________________________________
> 
> > > 
> 
> > > Help-glpk mailing list
> 
> > > 
> 
> > > address@hidden
> 
> > > 
> 
> > > https://lists.gnu.org/mailman/listinfo/help-glpk
> 
> 
> 
> -- 
> 
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