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mono-shlib-cop(1)	    General Commands Manual	     mono-shlib-cop(1)

NAME
       mono-shlib-cop -	Shared Library Usage Checker

SYNOPSIS
       mono-shlib-cop [OPTIONS]* [ASSEMBLY-FILE-NAME]*

OPTIONS
       -p, --prefixes=PREFIX
	      Mono   installation   prefixes.	 This	is   to	  find	 $pre-
	      fix/etc/mono/config.  The	default	is based upon the location  of
	      mscorlib.dll, and	is normally correct.

DESCRIPTION
       mono-shlib-cop  is  a tool that inspects	a managed assembly looking for
       erroneous or suspecious usage of	shared libraries.

       The tool	takes one or more assembly filenames, and inspects each	assem-
       bly specified.

       The errors checked for include:

       *      Does the shared library exist?

       *      Does the requested symbol	exist within the shared	library?

       The warnings checked for	include:

       *      Is  the  target  shared  library a versioned library?  (Relevant
	      only on Unix systems, not	Mac OS X or Windows.)

       In general, only	versioned libraries such as libc.so.6 are  present  on
       the  user's  machine, and efforts to load libc.so will result in	a Sys-
       tem.DllNotFoundException.  There	are three solutions to this:

       1.     Require that the user install any	-devel packages	which  provide
	      the  unversioned	library.   This	usually	requires that the user
	      install a	large number of	additional packages, complicating  the
	      installation process.

       2.     Use  a  fully versioned name in your DllImport statements.  This
	      requires editing your source code	and recompiling	 whenever  you
	      need to target a different version of the	shared library.

       3.     Provide  an  assembly.config  file which contains	<dllmap/> ele-
	      ments to remap the shared	library	name used by your assembly  to
	      the actual versioned shared library present on the users system.
	      Mono provides a number of	pre-existing  <dllmap/>	 entries,  in-
	      cluding ones for libc.so and libX11.so.

EXAMPLE
       The following code contains examples of the above errors	and warnings:
	    using System.Runtime.InteropServices; // for DllImport
	    class Demo {
		 [DllImport ("bad-library-name")]
		 private static	extern void BadLibraryName ();

		 [DllImport ("libc.so")]
		 private static	extern void BadSymbolName ();

		 [DllImport ("libcap.so")]
		 private static	extern int cap_clear (IntPtr cap_p);
	    }

       Bad library name
	      Assuming that the	library	bad-library-name doesn't exist on your
	      machine, Demo.BadLibraryName will	generate an error, as  it  re-
	      quires a shared library which cannot be loaded.  This may	be ig-
	      norable; see BUGS

       Bad symbol name
	      Demo.BadSymbolName will generate an error, as libc.so  (remapped
	      to  libc.so.6  by	 mono's	 $prefix/etc/mono/config file) doesn't
	      contain the function BadSymbolName

       Unversioned library dependency
	      Assuming you have	the file libcap.so , Demo.cap_clear will  gen-
	      erate  a	warning	because, while libcap.so could be loaded, lib-
	      cap.so might not exist on	the users machine (on  FC2,  /lib/lib-
	      cap.so  is  provided by libcap-devel , and you can't assume that
	      end users	will have any -devel packages installed).

FIXING CODE
       The fix depends on the warning or error:

       Bad library names
	      Use a valid library name in the DllImport	attribute, or  provide
	      a	 <dllmap/>  entry to map your existing library name to a valid
	      library name.

       Bad symbol names
	      Reference	a symbol that actually exists in the target library.

       Unversioned library dependency
	      Provide a	<dllmap/> entry	to reference a properly	versioned  li-
	      brary, or	ignore the warning (see	BUGS ).

DLLMAP ENTRIES
       Mono looks for an ASSEMBLY-NAME mapping information.  For example, with
       mcs.exe , Mono would read mcs.exe.config	,  and	for  Mono.Posix.dll  ,
       Mono would read Mono.Posix.dll.config

       The  .config file is an XML document containing a top-level <configura-
       tion/> section with nested <dllmap/> entries, which  contains  dll  and
       target  attributes.   The  dll attribute	should contain the same	string
       used in your DllImport attribute	value, and the target attribute	speci-
       fies which shared library mono should actually load at runtime.

       A sample	.config	file is:
	    <configuration>
		 <dllmap dll="gtkembedmoz" target="libgtkembedmoz.so" />
	    </configuration>

BUGS
       *      Only  DllImport  entries	are checked; the surrounding IL	is ig-
	      nored.  Consequently, if a runtime check is performed to	choose
	      which  shared  library to	invoke,	an error will be reported even
	      though the specified library is never used.  Consider this code:
		   using System.Runtime.InteropServices; // for	DllImport
		   class Beep {
			[DllImport ("kernel32.dll")]
			private	static extern int Beep (int dwFreq, int	dwDuration);

			[DllImport ("libcurses.so")]
			private	static extern int beep ();

			public static void Beep	()
			{
			     if	(System.IO.Path.DirectorySeparatorChar == '\\')	{
				  Beep (750, 300);
			     }
			     else {
				  beep ();
			     }
			}
		   }
	      If mono-shlib-cop	is run on this assembly, an error will be  re-
	      ported  for  using  kernel32.dll , even though kernel32.dll will
	      never be used on Unix platforms.

       *      mono-shlib-cop currently only examines the shared	 library  file
	      extension	 to determine if a warning should be generated.	 A .so
	      extension	will always generate a warning,	even if	the .so	is not
	      a	 symlink,  isn't provided in a -devel package, and there is no
	      versioned	  shared   library   (possible	 examples    including
	      /usr/lib/libtcl8.4.so, /usr/lib/libubsec.so, etc.).

	      Consequently,  warnings  for any such libraries are useless, and
	      incorrect.

	      Windows and Mac OS X will	 never	generate  warnings,  as	 these
	      platforms	use different shared library extensions.

MAILING	LISTS
       Visit  http://lists.ximian.com/mailman/listinfo/mono-devel-list for de-
       tails.

WEB SITE
       Visit http://www.mono-project.com for details

							     mono-shlib-cop(1)

NAME | SYNOPSIS | OPTIONS | DESCRIPTION | EXAMPLE | FIXING CODE | DLLMAP ENTRIES | BUGS | MAILING LISTS | WEB SITE

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