Provided by: mono-devel_6.8.0.105+dfsg-2_all 
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 $prefix/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 assembly 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 System.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/> elements 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, including 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 requires a shared library which
cannot be loaded. This may be ignorable; 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 generate a warning
because, while libcap.so could be loaded, libcap.so might not exist on the users
machine (on FC2, /lib/libcap.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 library, 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 <configuration/> 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 specifies 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 ignored. 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 reported 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 details.
WEB SITE
Visit http://www.mono-project.com for details
mono-shlib-cop(1)