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

[Nigel Galloway]

SetLastError is unnecessary, so sure leave that out.

By the same logic the unsafe keyword is unnecessary, so why not leave it
out.

SetLastError does no harm but code marked unsafe is not verified by the
Common Language Runtime, which if you are a C# programmer is
undesirable.

-- 
  Nigel Galloway
  address@hidden

On Mon, Apr 13, 2015, at 04:30 AM, Heinrich Schuchardt wrote:
> 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
> > 
> > 
> > 
> > -- 
> > 
> > http://www.fastmail.com - Access all of your messages and folders
> > 
> >                           wherever you are

-- 
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