mono-config - Mono runtime file format configuration
The Mono runtime will load configuration data from the installation
prefix /etc/mono/config file, the ~/.mono/config or from the file
pointed by the MONO_CONFIG environment variable.
For each assembly loaded a config file with the name:
/path/to/the/assembly.exe.config is loaded as well as the
This file controls the behavior of the runtime.
The file contains an XML-like file with various sections, all of them
contained inside a section (It actually uses GMarkup to parse the
This page describes the Unix-specific and Mono-specific extensions to
the configuration file; For complete details, see the
http://www.mono-project.com/Config web page.
You use the dllmap directive to map shared libraries referenced by
P/Invoke in your assemblies to a different shared library.
This is typically used to map Windows libraries to Unix library names.
The dllmap element takes two attributes:
dll This should be the same string used in the DllImport attribute,
optionally prefixed with "i:" to indicate that the string must
be matched in a case-insensitive way
target This should be the name of the library where the function can be
found: this name should be suitable for use with the platform
native shared library loading routines (dlopen etc.), so you may
want to check the manpages for that, too.
This directive can be used to map a specific dll/function pair to a
different library and also a different function name. It should appear
inside a dllmap element with only the dll attribute specified.
The dllentry element takes 3 attributes:
dll This is the target library, where the function can be found.
name This is the name of the function as it appears in the metadata:
it is the name of the P/Invoke method.
target This is the name of the function to lookup instead of the name
specified in the P/Invoke method.
Mapping based on operating system and cpu
Both the dllmap and the dllentry elements allow the following two
attributes which make it easy to use a single configuration file and
support multiple operating systems and architectures with different
os This is the name of the operating system for which the mapping
should be applied. Allowed values are: linux, osx, solaris,
freebsd, openbsd, netbsd, windows, aix, hpux.
cpu This is the name of the architecture for which the mapping
should be applied. Allowed values are: x86, x86-64, sparc, ppc,
s390, s390x, arm, mips, alpha, hppa, ia64.
This is the size of registers on the target architecture, it can
be either 32 or 64.
The attribute value for both attributes can be a comma-separated list
of the allowed values. Additionally, the first character may be a '!'
to reverse the meaning. An attribute value of "!windows,osx", for
example, would mean that the entry is considered on all operating
systems, except on Windows and OS X. No spaces are allowed in any part
of the value.
Note that later entries will override the entries defined earlier in
The following example maps references to the `cygwin1.dll' shared
library to the `libc.so.6' file.
<dllmap dll="i:cygwin1.dll" target="libc.so.6"/>
The library name in the DllImport attribute is allowed to be in any
case variant, like the following examples:
This one maps the following C# method:
static extern void somefunction ();
to differentfunction in libdifferent.so , but to the same function in
the library libanother.so when running under the Solaris and FreeBSD
<dllentry dll="libdifferent.so" name="somefunction" target="differentfunction" />
<dllentry os="solaris,freebsd" dll="libanother.so" name="somefunction" target="differentfunction" />