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# DMD Compiler for Windows

- Requirements and Downloads
- Installation
- Example
- Compiler Arguments and Switches
- Files
- Linking
- Environment Variables
- sc.ini Initialization File
- Common Installation Problems
- Differences between Windows and Linux versions
- D Interface Files
- Building Libraries
- Compiling dmd
- Compiling Phobos

## Requirements and Downloads

1. DMD Compiler
2. Windows operating system, Windows 7 or later, 32 or 64 bit
3. Download dmc.zip (C and C++ compiler) for Win32 (not required, but it complements dmd for Windows)

## Installation

Hint - The official installer performs these steps automatically.

Open a console window (for Windows this is done by clicking on [Start][Command Prompt]). All the tools are command line tools, which means they are run from a console window. Switch to the root directory. Unzip the files in the root directory. dmd.zip will create a \dmd2 directory with all the files in it. dmc.zip will create a \dm directory with all the files in it.

A typical session might look like:

    C:\Documents and Settings\Your Name>cd \
    C:\>unzip dmd.zip
    C:\>unzip dmc.zip

##

## Example

Run:

    \dmd2\windows\bin\shell all.sh

in the \dmd2\samples\d directory for several small examples.

## Compiler Arguments and Switches

dmd files... -switches...
files...

  File Extensions
  Extension | File Type
  --- | ---
  none | D source files
  .c | C source files
  .d | D source files
  .dd | Ddoc source files
  .di | D interface files
  .i | preprocessed C source files
  .obj | Object files to link in
  .lib | Object code libraries to search
  .exe | Output executable file
  .def | module definition file
  .res | resource file

@cmdfile
  If cmdfile is an environment variable, read the compiler arguments and switches from the value of that variable. Otherwise, read compiler arguments and switches from the text file cmdfile. The file may contain single-line comments starting with the hash symbol (#).
-allinst
  Generate code for all template instantiations
-betterC
  Adjusts the compiler to implement D as a better C:
  - Predefines D_BetterC version.
  - Assert Expressions, when they fail, call the C runtime library assert failure function rather than a function in the D runtime.
  - Array overflows call the C runtime library assert failure function rather than a function in the D runtime.
  - Final switch errors call the C runtime library assert failure function rather than a function in the D runtime.
  - Does not automatically link with phobos runtime library.
  - Module constructors and destructors are not generated meaning that static and shared static constructors and destructors will not get called.
  - ModuleInfo is not generated.
  - TypeInfo instances will not be generated for structs.
-boundscheck=[on|safeonly|off ]
  Controls if bounds checking is enabled.
  - on: Bounds checks are enabled for all code. This is the default.
  - safeonly: Bounds checks are enabled only in @safe code. This is the default for -release builds.
  - off: Bounds checks are disabled completely (even in @safe code). This option should be used with caution and as a last resort to improve performance. Confirm turning off @safe bounds checks is worthwhile by benchmarking.
-c
  Compile only, do not link
-check=[assert|bounds|in|invariant|out|switch ][=[on|off]]
  Overrides default, -boundscheck, -release and -unittest options to enable or disable specific checks.
  - assert: assertion checking
  - bounds: array bounds
  - in: in contracts
  - invariant: class/struct invariants
  - out: out contracts
  - switch: finalswitch failure checking
  - on or not specified: specified check is enabled.
  - off: specified check is disabled.
-check=[h|help|? ]
  List information on all available checks
-checkaction=[D|C|halt|context ]
  Sets behavior when an assert fails, and array boundscheck fails, or a final switch errors.
  - D: Default behavior, which throws an unrecoverable AssertError.
  - C: Calls the C runtime library assert failure function.
  - halt: Executes a halt instruction, terminating the program.
  - context: Prints the error context as part of the unrecoverable AssertError.
-checkaction=[h|help|? ]
  List information on all available check actions
-color
  Turn colored console output on
-color=[on|off|auto ]
  Show colored console output. The default depends on terminal capabilities.
  - auto: use colored output if a tty is detected (default)
  - on: always use colored output.
  - off: never use colored output.
-conf=filename
  Use config file at filename
-cov
  Do code coverage analysis
-cov=ctfe
  Include code executed during CTFE in coverage report
-cov=nnn
  Perform code coverage analysis and generate .lst file with report.

    dmd -cov -unittest myprog.d

-cpp=filename
  Normally the C preprocessor used by the associated C compiler is used to preprocess ImportC files, this is overridden by the -cpp switch.
-D

  Generate documentation from source.

  Note: mind the security considerations.

-Dd directory
  Write documentation file to directory . -op can be used if the original package hierarchy should be retained
-Df filename
  Write documentation file to filename
-d
  Silently allow deprecated features and use of symbols with deprecated attributes.
-de
  Issue an error when deprecated features or symbols are used (halt compilation)
-dw
  Issue a message when deprecated features or symbols are used (default)
-debug
  Compile in debug code
-debug=level
  Compile in debug level <= level
-debug=ident
  Compile in debug identifier ident
-debuglib=name
  Link in libname as the default library when compiling for symbolic debugging instead of phobos.lib. If libname is not supplied, then no default library is linked in.
-defaultlib=name
  Link in libname as the default library when not compiling for symbolic debugging instead of phobos.lib. If libname is not supplied, then no default library is linked in.
-deps
  Print module dependencies (imports/file/version/debug/lib)
-deps=filename
  Without filename, print module dependencies (imports/file/version/debug/lib). With filename, write module dependencies as text to filename (only imports).
-extern-std=standard
  Standards supported are:
  - c++98: Use C++98 name mangling, Sets __traits(getTargetInfo, "cppStd") to 199711
  - c++11 (default): Use C++11 name mangling, Sets __traits(getTargetInfo, "cppStd") to 201103
  - c++14: Use C++14 name mangling, Sets __traits(getTargetInfo, "cppStd") to 201402
  - c++17: Use C++17 name mangling, Sets __traits(getTargetInfo, "cppStd") to 201703
  - c++20: Use C++20 name mangling, Sets __traits(getTargetInfo, "cppStd") to 202002
-extern-std=[h|help|? ]
  List all supported standards
-fPIC
  Generate position independent code
-fPIE
  Generate position independent executables
-g
  Add CodeView symbolic debug info. See Debugging on Windows.
-gdwarf=version
  The value of version may be 3, 4 or 5, defaulting to 3.
-gf
  Symbolic debug info is emitted for all types referenced by the compiled code, even if the definition is in an imported file not currently being compiled.
-gs
  Always emit stack frame
-gx
  Adds stack stomp code, which overwrites the stack frame memory upon function exit.
-H
  Generate D interface file
-Hd=directory
  Write D interface file to dir directory. -op can be used if the original package hierarchy should be retained.
-Hf=filename
  Write 'header' file to filename
-HC[=[silent|verbose ]]
  Generate C++ 'header' files using the given configuration:",
  silent
    only list extern(C[++]) declarations (default)
  verbose
    also add comments for ignored declarations (e.g. extern(D))
-HC=[?|h|help ]
  List available modes for C++ 'header' file generation
-HCd=directory
  Write C++ 'header' file to directory
-HCf=filename
  Write C++ 'header' file to filename
--help
  Print help and exit
-I=directory
  Look for imports also in directory
-i[=pattern ]

  Enables "include imports" mode, where the compiler will include imported modules in the compilation, as if they were given on the command line. By default, when this option is enabled, all imported modules are included except those in druntime/phobos. This behavior can be overriden by providing patterns via -i=<pattern>. A pattern of the form -i=<package> is an "inclusive pattern", whereas a pattern of the form -i=-<package> is an "exclusive pattern". Inclusive patterns will include all module's whose names match the pattern, whereas exclusive patterns will exclude them. For example. all modules in the package foo.bar can be included using -i=foo.bar or excluded using -i=-foo.bar. Note that each component of the fully qualified name must match the pattern completely, so the pattern foo.bar would not match a module named foo.barx.

  The default behavior of excluding druntime/phobos is accomplished by internally adding a set of standard exclusions, namely, -i=-std -i=-core -i=-etc -i=-object. Note that these can be overriden with -i=std -i=core -i=etc -i=object.

  When a module matches multiple patterns, matches are prioritized by their component length, where a match with more components takes priority (i.e. pattern foo.bar.baz has priority over foo.bar).

  By default modules that don't match any pattern will be included. However, if at least one inclusive pattern is given, then modules not matching any pattern will be excluded. This behavior can be overriden by usig -i=. to include by default or -i=-. to exclude by default.

  Note that multiple -i=... options are allowed, each one adds a pattern.

-ignore
  Ignore unsupported pragmas
-inline
  Inline functions at the discretion of the compiler. This can improve performance, at the expense of making it more difficult to use a debugger on it.
-J=directory
  Where to look for files for ImportExpressions. This switch is required in order to use ImportExpressions. path is a ; separated list of paths. Multiple -J's can be used, and the paths are searched in the same order.
-L=linkerflag
  Pass linkerflag to the linker optlink.exe , for example, ld
-lib
  Generate library file as output instead of object file(s). All compiled source files, as well as object files and library files specified on the command line, are inserted into the output library. Compiled source modules may be partitioned into several object modules to improve granularity. The name of the library is taken from the name of the first source module to be compiled. This name can be overridden with the -of switch.
-lowmem
  Enable the garbage collector for the compiler, reducing the compiler memory requirements but increasing compile times.
-m32
-m32mscoff
  Generate 32 bit code and write MS-COFF object files (deprecated use -m32)
-m32omf
  Compile a 32 bit executable. The generated object code is in OMF and is meant to be used with the Digital Mars C/C++ compiler.
-m64
  The generated object code is in MS-COFF and is meant to be used with the Microsoft Visual Studio 10 or later compiler.
-main
  Add a default main() function when compiling. This is useful when unittesting a library, as it enables running the unittests in a library without having to manually define an entry-point function.
-makedeps[=filename ]
  Print dependencies in Makefile compatible format. If filename is omitted, it prints to stdout. The emitted targets are the compiled artifacts (executable, object files, libraries). The emitted dependencies are imported modules and imported string files (via -J switch). Special characters in a dependency or target filename are escaped in the GNU Make manner.
-man
  Open default browser on this page
-map
  Generate a .map file
-mcpu=id
  Set the target architecture for code generation, where:
  help
    list alternatives
  baseline
    the minimum architecture for the target platform (default)
  avx
    generate AVX instructions instead of SSE instructions for vector and floating point operations. Not available for 32 bit memory models other than OSX32.
  native
    use the architecture the compiler is running on
-mcpu=[h|help|? ]
  List all architecture options
-mixin=filename
  Expand and save mixins to file specified by filename
-mscrtlib=libname
  If building MS-COFF object files when targeting Windows, embed a reference to the given C runtime library libname into the object file containing main, DllMain or WinMain for automatic linking. The default is libcmt (release version with static linkage), the other usual alternatives are libcmtd, msvcrt and msvcrtd. If no Visual C installation is detected, a wrapper for the redistributable VC2010 dynamic runtime library and mingw based platform import libraries will be linked instead using the LLD linker provided by the LLVM project. The detection can be skipped explicitly if msvcrt120 is specified as libname. If libname is empty, no C runtime library is automatically linked in.
-mv=package.module =
  Use path/filename as the source file for package.module. This is used when the source file path and names are not the same as the package and module hierarchy. The rightmost components of the path/filename and package.module can be omitted if they are the same.
-noboundscheck
  Turns off all array bounds checking, even for safe functions. Deprecated (use -boundscheck=off instead).
-O
  Optimize generated code. For fastest executables, compile with the -O -release -inline -boundscheck=off switches together.
-o-
  Suppress generation of object file. Useful in conjuction with -D or -H flags.
-od=directory
  Write object files relative to directory objdir instead of to the current directory. -op can be used if the original package hierarchy should be retained
-of=filename
  Set output file name to filename in the output directory. The output file can be an object file, executable file, or library file depending on the other switches.
-op
  Normally the path for .d source files is stripped off when generating an object, interface, or Ddoc file name. -op will leave it on.
-os=os
  Set the target operating system as other than the host.
  - host: Target the host operating system (default).
  - dragonflybsd: DragonFlyBSD
  - freebsd: FreeBSD
  - linux: Linux
  - openbsd: OpenBSD
  - osx: OSX
  - solaris: Solaris
  - windows: Windows
-P=preprocessorflag
  Pass preprocessorflag to sppn.exe or cl.exe
-preview=name
  Preview an upcoming language change identified by id
-preview=[h|help|? ]
  List all upcoming language changes
-profile
  Instrument the generated code so that runtime performance data is collected when the generated program is run. Upon completion of the generated program, the files trace.log and trace.def are generated. trace.log has two sections,
  1. Fan in and fan out for each profiled function. The name of the function is left-justified, the functions immediately preceding it are the other functions that call it (fan in) and how many times it is called. The functions immediately following are the functions that are called (fan out) and how many times it calls that function. The function itself has 3 numbers appended: the aggregate of the fan in counts, the tree time used by the function which is the function time plus the tree times of all the functions it calls, and the time used excluding the time used by fan out.
  2. Timing data for each function, sorted from most used to least.
  The trace.def file contains linker commands to associate functions which are strongly coupled so they appear adjacent in the resulting executable file. For more information see profile
-profile=gc
  - gc: Instrument calls to GC memory allocation and write a report to the file profilegc.log upon program termination. Note: Only instrumented calls will be logged. These include:
    - Language constructs that allocate memory
    - Phobos functions that allocate GC memory
    - GC allocations via core.memory.GC
    Allocations made by other means will not be logged, including direct calls to the GC's C API.
-release
  Compile release version, which means not emitting run-time checks for contracts and asserts. Array bounds checking is not done for system and trusted functions, and assertion failures are undefined behaviour.
-revert=name
  Revert language change identified by id
-revert=[h|help|? ]
  List all revertable language changes
-run srcfile
  Compile, link, and run the program srcfile with the rest of the command line, args..., as the arguments to the program. No .obj or executable file is left behind.
-shared
  Generate DLL library
-target=triple
  arch is the architecture: either x86, x64, x86_64 or x32, vendor is always ignored, but supported for easier interoperability, os is the operating system, this may have a trailing version number: freestanding for no operating system, darwin or osx for MacOS, dragonfly or dragonflybsd for DragonflyBSD, freebsd, openbsd, linux, solaris or windows for their respective operating systems. cenv is the C runtime environment and is optional: musl for musl-libc, msvc for the MSVC runtime (the default for windows with this option), bionic for the Andriod libc, digital_mars for the Digital Mars runtime for Windows gnu or glibc for the GCC C runtime, newlib or uclibc for their respective C runtimes. ($ I cppenv) is the C++ runtime environment: clang for the LLVM C++ runtime gcc for GCC's C++ runtime, msvc for microsoft's MSVC C++ runtime (the default for windows with this switch), sun for Sun's C++ runtime and digital_mars for the Digital Mars C++ runtime for windows.
-transition=name
  Show additional info about language change identified by id
-transition=[h|help|? ]
  List all language changes
-unittest
  Compile in unittest code, turns on asserts, and sets the unittest version identifier
-v
  Enable verbose output for each compiler pass
-vasm
  List generated assembler for each function
-vcolumns
  Print character (column) numbers in diagnostics
-verror-style=[digitalmars|gnu ]
  Set the style for file/line number annotations on compiler messages, where:
  digitalmars
    'file(line[,column]): message'. This is the default.
  gnu
    'file:line[:column]: message', conforming to the GNU standard used by gcc and clang.
-verror-supplements=num
  Limit the number of supplemental messages for each error (0 means unlimited)
-verrors=num
  Limit the number of error messages (0 means unlimited)
-verrors=context
  Show error messages with the context of the erroring source line
-verrors=spec
  Show errors from speculative compiles such as __traits(compiles,...)
--version
  Print compiler version and exit
-version=level
  Compile in version level >= level
-version=ident
  Compile in version identifier ident
-vgc
  List all gc allocations including hidden ones
-vtls
  List all variables going into thread local storage
-vtemplates=[list-instances ]
  An optional argument determines extra diagnostics, where:
  list-instances
    Also shows all instantiation contexts for each template.
-w
  Enable warnings
-wi
  Enable informational warnings (i.e. compilation still proceeds normally)
-X
  Generate JSON file
-Xf=filename
  Write JSON file to filename
-Xcc=driverflag
  Pass driverflag to the linker driver ($CC or cc)

Empty switches, i.e. "", are ignored.

## Files

\dmd2\src\phobos\
  D runtime library source
\dmd2\src\dmd\
  D compiler front end source under dual (GPL and Artistic) license
\dmd2\html\d\
  Documentation
\dmd2\samples\d\
  Sample D programs
\dmd2\windows\bin\ddemangle.exe
  D symbol demangler
\dmd2\windows\bin\dman.exe
  D manual lookup tool
\dmd2\windows\bin\dmd.exe
  D compiler executable
\dmd2\windows\bin$(DUB)
  D's package manager
\dmd2\windows\bin$(DUSTMITE)
  D source code minimizer
\dmd2\windows\bin$(OPTLINK)
  OPTLINK
\dmd2\windows\bin$(LINK2 http://www.digitalmars.com/ctg/make.html, make.exe)
  Digitalmars Make
\dmd2\windows\bin\replace.exe
  Find/replace text in files
\dmd2\windows\bin$(RDMD)
  D build tool for script-like D code execution
\dmd2\windows\bin\sc.ini
  Global compiler settings
\dmd2\windows\bin$(LINK2 http://www.digitalmars.com/ctg/shell.html, shell.exe)
  Simple command line shell
\dmd2\windows\lib$(LIB)
  D runtime library

## Linking

Linking is done directly by the dmd compiler after a successful compile. To prevent dmd from running the linker, use the -c switch.

32 bit programs must be linked with the D runtime library phobos.lib, followed by the Digital Mars C runtime library snn.lib. This is done automatically as long as the directories for the libraries are on the LIB environment variable path. A typical way to set LIB would be:

    set LIB=\dmd2\lib;\dm\lib

If the dmd command is used to both compile and link to an executable, it will make certain optimizations that are valid only for Windows executable files. Do not use the resulting .obj files in a DLL. To compile modules into .obj files that can be used in an exe or DLL, compile with -c and -shared.

Linking 32 bit programs is done using Digital Mars optlink.exe.

Linking 64 bit programs is done using the Microsoft linker by default. If the Microsoft linker is not found, the included LLVM linker LLD will be used.

## Environment Variables

The D compiler dmd uses the following environment variables:

DFLAGS
  The value of DFLAGS is treated as if it were appended to the command line to dmd.exe.
LIB
  The linker uses LIB to search for library files. For D, it will normally be set to:

    set LIB=\dmd2\lib;\dm\lib

LINKCMD
  dmd normally runs the linker by looking for optlink.exe along the PATH. To use a specific linker for 32 bit programs instead, set the LINKCMD environment variable to it. For example:

    set LINKCMD=\dmd\windows\bin\link

LINKCMD64
  dmd normally runs the linker by looking for optlink.exe along the PATH. To use a specific linker for 64 bit programs instead, set the LINKCMD64 environment variable to it. For example:

    set LINKCMD64=C:\Program Files (x86)\Microsoft Visual Studio 15.0\VC\bin\amd64\link.exe

PATH
  If the linker is not found in the same directory as dmd.exe is in, the PATH is searched for it. Note: other linkers named link.exe will likely not work. Make sure the Digital Mars optlink.exe is found first in the PATH before other link.exes, or use LINKCMD to specifically identify which linker to use.

## sc.ini Initialization File

dmd will look for the initialization file sc.ini in the following sequence of directories:

1. current working directory
2. directory specified by the HOME environment variable
3. directory dmd.exe resides in

If found, environment variable settings in the file will override any existing settings. This is handy to make dmd independent of programs with conflicting use of environment variables.

### Initialization File Format

Comments are lines that begin with ; and are ignored.

Environment variables follow the [Environment] section heading, in NAME=value pairs. The NAMEs are treated as upper case. Comments are lines that start with ;. For example:

    ; sc.ini file for dmd
    ; Names enclosed by %% are searched for in the existing environment
    ; and inserted. The special name %@P% is replaced with the path
    ; to this file.
    [Environment]
    LIB="%@P%..\lib";\dm\lib

    DFLAGS="-I%@P%..\src\phobos" "-I%@P%..\src\druntime\import"
    LINKCMD="%@P%....\dm\bin"
    DDOCFILE=mysettings.ddoc

### Location Independence of sc.ini

The %@P% is replaced with the path to sc.ini. Thus, if the fully qualified file name sc.ini is c:\dmd2\bin\sc.ini, then %@P% will be replaced with c:\dmd2\bin, and the above sc.ini will be interpreted as:

    [Environment]
    LIB="c:\dmd2\bin..\lib";\dm\lib

    DFLAGS="-Ic:\dmd2\bin..\src\phobos" "-Ic:\dmd2\bin..\src\druntime\import"
    LINKCMD="c:\dmd2\bin....\dm\bin"
    DDOCFILE=mysettings.ddoc

This enables your dmd setup to be moved around without having to re-edit sc.ini.

## Common Installation Problems

- Using Cygwin's unzip utility has been known to cause strange problems.
- Running the compiler under Cygwin's command shell has been also known to cause problems. Try getting it to work under the regular Windows shell cmd.exe before trying Cygwin's.
- Installing dmd and dmc into directory paths with spaces in them causes problems.

## Differences between Windows and Linux versions

- String literals are read-only under Linux. Attempting to write to them will cause a segment violation.

## D Interface Files

When an import declaration is processed in a D source file, the compiler searches for the D source file corresponding to the import, and processes that source file to extract the information needed from it. Alternatively, the compiler can instead look for a corresponding D interface file. A D interface file contains only what an import of the module needs, rather than the whole implementation of that module.

The advantages of using a D interface file for imports rather than a D source file are:

- D interface files are often significantly smaller and much faster to process than the corresponding D source file.
- They can be used to hide the source code, for example, one can ship an object code library along with D interface files rather than the complete source code.

D interface files can be created by the compiler from a D source file by using the -H switch to the compiler. D interface files have the .di file extension. When the compiler resolves an import declaration, it first looks for a .di D interface file, then it looks for a D source file.

D interface files bear some analogous similarities to C++ header files. But they are not required in the way that C++ header files are, and they are not part of the D language. They are a feature of the compiler, and serve only as an optimization of the build process.

## Building Executables

dmd can build an executable much faster if as many of the source files as possible are put on the command line.

Another advantage to putting multiple source files on the same invocation of dmd is that dmd will be able to do some level of cross-module optimizations, such as function inlining across modules.

The -i flag can be used to automatically compile imported modules

## Building Libraries

There are three ways to build a library. For example, given foo.d and bar.d which are to be compiled, and existing object file abc.obj and existing library def.lib which are all to be combined into a library foo.lib:

1. Compile modules separately and then run the librarian on them:

       dmd -c foo.d
       dmd -c bar.d
       phobos.lib -c -p32 foo.lib foo.obj bar.obj abc.obj def.lib
       del foo.obj bar.obj

   This option is typical when using a makefile to avoid compiling modules that have already been compiled.
2. Compile modules together and then run the librarian on them:

       dmd -c foo.d bar.d
       phobos.lib -c -p32 foo.lib foo.obj bar.obj abc.obj def.lib
       del foo.obj bar.obj

3. Use dmd to compile and build library in one operation:

       dmd -lib foo.d bar.d abc.obj def.lib

   No object files are written to disk, it's all done in memory. Using -lib also has the advantage that modules may be compiled into multiple object files rather than exactly one per module. This improves granularity of the library without having to break up the modules.

## Compiling dmd

Complete source code is provided to build the compiler. Follow these steps:

    cd \dmd2\src\dmd
    make -f win32.mak

## Compiling Phobos

Complete source code is provided to build Phobos, the D runtime library. Follow these steps:

    cd \dmd2\src\druntime
    make -f win32.mak
    cd ..\phobos
    make -f win32.mak

Copyright © 1999-2023 by the D Language Foundation | Page generated by Ddoc on Sun Jul 2 00:31:15 2023