Navigation

Gendarme.Rules.Interoperability

From Mono

Gendarme's interoperability rules are located in the Gendarme.Rules.Interoperability.dll assembly. Latest sources are available from anonymous SVN (http://anonsvn.mono-project.com/viewcvs/trunk/mono-tools/gendarme/rules/Gendarme.Rules.Interoperability/) (tarball (http://anonsvn.mono-project.com/viewcvs/trunk/mono-tools/gendarme/rules/Gendarme.Rules.Interoperability.tar.gz?view=tar)).

Table of contents
1 Rules

1.1 CallGetLastErrorAfterPInvokeRule
1.2 MarshalStringsInPInvokeDeclarationsRule
1.3 PInvokeShouldNotBeVisibleRule
1.4 UseManagedAlternativesToPInvokeRule

2 Feedback

Rules


CallGetLastErrorAfterPInvokeRule

Marshal.GetLastWin32Error() should be called directly after a PInvoke call. Intermediate method calls, even managed, could overwrite the error code.

Bad example: 

public void DestroyError ()
{
    MessageBeep (2);
    Console.WriteLine ("Beep");
    int error = Marshal.GetLastWin32Error ();
}

Good example: 

public void GetError ()
{
    MessageBeep (2);
    int error = Marshal.GetLastWin32Error ();
    Console.WriteLine ("Beep");
}
 
public void DontUseGetLastError ()
{
    MessageBeep (2);
    Console.WriteLine ("Beep");
}

MarshalStringsInPInvokeDeclarationsRule

This rule warns the developer if the CharSet has not been specified for string parameters of P/Invoke method, unless if they are individually decorated with [MarshalAs] attribute. This applies to any System.String and System.Text.StringBuilder parameters.

Bad example: 

[DllImport("coredll.dll")]
static extern int SHCreateShortcut (StringBuilder szShortcut, StringBuilder szTarget);

Good examples: 

[DllImport("coredll.dll", CharSet = CharSet.Auto)]
static extern int SHCreateShortcut (StringBuilder szShortcut, StringBuilder szTarget);
 
[DllImport("coredll.dll")]
static extern int SHCreateShortcut ([MarshalAs(UnmanagedType.LPTStr)] StringBuilder szShortcut, 
    [MarshalAs(UnmanagedType.LPTStr)] StringBuilder szTarget);

PInvokeShouldNotBeVisibleRule

This rule checks for PInvoke declaration methods that are visible outside their assembly.

Bad example: 

[DllImport ("user32.dll")]
public static extern bool MessageBeep (UInt32 beepType);

Good example: 

[DllImport ("user32.dll")]
internal static extern bool MessageBeep (UInt32 beepType);


UseManagedAlternativesToPInvokeRule

This rule warns the developer if certain external (P/Invoke) methods are being called in case they have managed alternatives provided by the .NET framework.

Bad example: 

[DllImport ("kernel32.dll")]
static extern void Sleep (uint dwMilliseconds);
 
public void WaitTwoSeconds ()
{
   Sleep (2000);
}

Good example: 

public void WaitTwoSeconds ()
{
   System.Threading.Thread.Sleep (2000);
}

Feedback

Please report any documentation errors, typos or suggestions to the Gendarme Google Group (http://groups.google.com/group/gendarme). Thanks!

Retrieved from "http://www.mono-project.com/Gendarme.Rules.Interoperability"