libxlsxwriter/docs/src/getting_started.dox

/**
@page getting_started Getting Started with libxlsxwriter

@tableofcontents

Here are some instructions to get you up and running with the libxlsxwriter
library on different OSes.


@section gsg_quick_start Quick-start on Linux

If you prefer to assemble Ikea furniture first and only read the instructions
when you have parts left over then the following minimal set of commands
should get you up and running on a Debian like system:

    sudo apt-get install -y zlib1g-dev
    git clone https://github.com/jmcnamara/libxlsxwriter.git
    cd libxlsxwriter
    make
    sudo make install

If you read the instructions first and then assemble the furniture you will
know how to proceed.


@section gsg_linux Installation on Linux

@subsection gsg_dependencies Install the dependencies

The only non-optional dependency when building libxlsxwriter is [Zlib](http://www.zlib.net).

You can install `zlib` from source as follows:

    curl -O -L  http://www.zlib.net/zlib-1.2.11.tar.gz
    tar zxf zlib-1.2.11.tar.gz
    cd zlib-1.2.11

    ./configure
    make

    sudo make install

Alternatively, you can use your OS packager to install the `zlib` development
libraries. For example:

    sudo apt-get install -y zlib1g-dev

The zlib version must be >= 1.2.8 to avoid compilation issues.

@note There are optional dependencies that can be installed for testing.
See @ref running_the_tests.


@subsection gsg_git Get the source code

To get the latest version of the source code you can clone the libxlsxwriter
repository from GitHub:

    git clone https://github.com/jmcnamara/libxlsxwriter.git

Alternatively you can get a tarball of the latest source code as follows:

    curl -O -L http://github.com/jmcnamara/libxlsxwriter/archive/master.tar.gz


@subsection gsg_build Build the source code

Build the source code as follows:

    cd libxlsxwriter
    make

This will create a static and dynamic library in the local `./lib` directory:

    ls lib
    libxlsxwriter.a     libxlsxwriter.so

To see a verbose summary of the compilation steps use `V=1`:

    make V=1

With CMake you can build the library as follows:

    mkdir build # Or another sub-directory.
    cd build
    cmake ..
    cmake --build .

@subsection gsg_examples Build the examples

If there weren't any warnings or errors in the previous step (and there
shouldn't have been) then you can build the programs in the `examples`
directory and try one of them out:

    # With Make:
    make examples

    # or CMake:
    mkdir build
    cd build
    cmake .. -DBUILD_EXAMPLES=ON
    cmake --build .

    # Then:
    ./examples/hello

This will create a `hello_world.xlsx` file in your current directory. Open the
file in a spreadsheet application. The output should look like this: @image
html hello01.png


@subsection gsg_install Install the library

Libxlsxwriter supports a simplified installation scheme for a static and
dynamic/shared library and header files.

    sudo make install

The files are installed to `/usr/local` by default but this can be overridden
by using the `PREFIX` environmental variable:

    make install PREFIX=/usr/third_party

A staging directory can be set with `DESTDIR` which is prepended to all
install paths. This is a an occasionally useful feature for packaging:

    make install PREFIX=/usr/third_party DESTDIR=./staging/

This would build and link the code with `/usr/third_party` as the
installation location but actually install to `./staging/usr/third_party`.

With CMake you can install the library as follows:

    mkdir build
    cd build
    cmake ..
    cmake --build . --target install

@subsection gsg_using Using the library

Using your source code editor create a file like the following called
`myexcel.c`:

@code
    #include "xlsxwriter.h"

    int main() {

        lxw_workbook  *workbook  = workbook_new("myexcel.xlsx");
        lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
        int row = 0;
        int col = 0;

        worksheet_write_string(worksheet, row, col, "Hello me!", NULL);

        return workbook_close(workbook);
    }
    @endcode

If you executed the install commands in the previous section then you
should be able to compile the program as follows:

    cc myexcel.c -o myexcel -lxlsxwriter

In some OS environments, or if you changed the `PREFIX` location, you may
have to provide explicit `include` and `lib` paths:

    cc myexcel.c -o myexcel -I/usr/local/include -L/usr/local/lib -lxlsxwriter

You can also use
[pkg-config](https://www.freedesktop.org/wiki/Software/pkg-config/)
(after installation of the library) to automatically determine the required
arguments and paths:

    $ pkg-config --cflags --libs xlsxwriter
    -I/usr/local/include -L/usr/local/lib -lxlsxwriter -lz

You can add this information to your compilation as follows:

    cc myexcel.c -o myexcel `pkg-config --cflags --libs xlsxwriter`

This will create an executable that you can run to generate an Excel
spreadsheet:

    ./myexcel
    xdg-open myexcel.xlsx

If the installation didn't work for you then you can link against the static
library you created in the "Build the source code" step:

    cc myexcel.c -o myexcel -I /path/to/libxlsxwriter/include \
                               /path/to/libxlsxwriter/lib/libxlsxwriter.a -lz


@section gsg_macos Installation on macOS and iOS

The easiest way to install libxlsxwriter for Xcode and iOS is to use the
CocoaPods method shown in the next section.

To install libxlsxwriter from the macOS commandline requires the
[Xcode "commandline tools"](https://developer.apple.com/xcode/resources/).
You can then follow the same instructions for compiling and installing on
Linux, as shown above.

For commandline access to libxlsxwriter you can also use
[brew/homebrew](https://brew.sh), see below.


@subsection gsg_cocoapods Install using CocoaPods for Xcode

For iOS and macOS projects in Xcode you can install libxlsxwriter using
[CocoaPods](https://cocoapods.org).

Add the following entry to your `Podfile`:

    pod 'libxlsxwriter', '~> 0.9'

if you are using Swift, you can now add an import:

    import xlsxwriter

And call its C functions like this:

    let documentDirectory = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor:nil, create:false)
    let fileURL = documentDirectory.appendingPathComponent("hello_world.xlsx")

    let workbook = workbook_new((fileURL.absoluteString.dropFirst(6) as NSString).fileSystemRepresentation)
    let worksheet = workbook_add_worksheet(workbook, nil)
    worksheet_write_string(worksheet, 0, 0, "Hello", nil)
    worksheet_write_number(worksheet, 1, 0, 123, nil)
    workbook_close(workbook)

For a sample Xcode project that uses the libxlsxwriter cocoapod for iOS and
macOS with Objective-C and Swift see [libxlsxwriter Cocoa
Examples](https://github.com/lrossi/libxlsxwriterCocoaExamples) or
[LibXlsxWriterSwiftSample](https://github.com/FrankenApps/LibXlsxWriterSwiftSample).


@subsection gsg_brew Installation on macOS with homebrew

On macOS you can also use [brew/homebrew](https://brew.sh):

    brew install libxlsxwriter

Once installed you can compile and run a libxlsxwriter program as follows:

    cc myexcel.c -o myexcel -I/usr/local/include -L/usr/local/lib -lxlsxwriter
    ./myexcel

@section gsg_windows Installation on Windows

There are several ways to compile libxlsxwriter on and for Windows, see below.


@subsection gsg_vcpkg Using vcpkg for Microsoft Visual Studio

The most convenient way to get the latest release version of libxlsxwriter and
integrate it into your Visual Studio build environment is to use the
[vcpkg](https://vcpkg.io) tool:

> vcpkg is a free C/C++ package manager for acquiring and managing
> libraries. Choose from over 1500 open source libraries to download and build
> in a single step or add your own private libraries to simplify your build
> process. Maintained by the Microsoft C++ team and open source contributors.


Install vcpkg and libxlsxwriter as follows in Windows CMD or Powershell:

    git clone https://github.com/microsoft/vcpkg.git
    cd vcpkg
    bootstrap-vcpkg.bat
    vcpkg install libxlsxwriter

You should then see libxlsxwriter installed as follows (note that the required
zlib dependency has also been installed):

    vcpkg list

      libxlsxwriter:x86-windows  0.8.6-1   Libxlsxwriter is a C library that ...
      zlib:x86-windows           1.2.11-5  A compression library

You can also install libxlsxwriter for other build targets like `x64`

    vcpkg install libxlsxwriter:x64-windows

    vcpkg list

      libxlsxwriter:x64-windows  1.1.4      Libxlsxwriter is a C library that ...
      libxlsxwriter:x86-windows  1.1.4      Libxlsxwriter is a C library that ...
      zlib:x64-windows           1.2.11#13  A compression library
      zlib:x86-windows           1.2.11#13  A compression library

To use libxlsxwriter from within Visual Studio you can "integrate" it into
your environment:

    vcpkg integrate install

      Applied user-wide integration for this vcpkg root.

All MSBuild C projects can now include libxlsxwriter directly. Linking will
also be handled automatically. For example, create a new Win32 Console (or
other C/C++) application in Visual Studio:

    File
      -> New
        -> Project

    Visual C++
      -> Win32
        -> Win32 Console Application

Replace the empty main with a libxlsxwriter example from the distro. For
example:

@code
// Some older versions on Visual Studio may need "stdafx.h".
// #include "stdafx.h"

#include "xlsxwriter.h"

int main() {

    lxw_workbook  *workbook = workbook_new("hello_world.xlsx");
    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);

    worksheet_write_string(worksheet, 0, 0, "Hello", NULL);
    worksheet_write_number(worksheet, 1, 0, 123, NULL);

    workbook_close(workbook);

    return 0;
}
@endcode

Change the target to "Release" and the architecture to "x86" or "x64"
(depending on the version you installed above). You can now "Build Solution".
The resulting executable will be put in the output directory with the required
"xlsxwriter.dll" and "zlib1.dll" files.


@subsection gsg_cmake_app Using CMake for Microsoft Visual Studio

For a more manual installation, and for older versions of Microsoft Visual
Studio or Windows, you can use CMake as shown below.

Open a Windows CMD or Command Window and set up your MSVC environment, if
required. Something like this:

    "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"

    # Or:
    "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvars64.bat"

Then create a work directory and an install directory that the include and
library files will be installed to. Set the follow variables to point to the
directories:

    set    WORK_DIR=C:/Users/Username/tmp
    set INSTALL_DIR=C:/Users/Username/tmp/install_dir

Build the Zlib library:

    cd %WORK_DIR%

    git clone https://github.com/madler/zlib.git
    cd zlib
    mkdir build
    cd    build

    cmake .. -G "Visual Studio 14 Win64" -DCMAKE_INSTALL_PREFIX:PATH="%INSTALL_DIR%/zlib"

    cmake --build . --config Release --target install

Build the libxlsxwriter library:

    cd %WORK_DIR%

    git clone https://github.com/jmcnamara/libxlsxwriter.git
    cd libxlsxwriter
    mkdir build
    cd    build

    cmake .. -G "Visual Studio 14 Win64" -DCMAKE_INSTALL_PREFIX:PATH="%INSTALL_DIR%/libxlsxwriter" -DZLIB_ROOT:STRING="%INSTALL_DIR%/zlib"

    cmake --build . --config Release --target install


Create a new Win32 Console (or other C/C++) application in Visual Studio:

    File
      -> New
        -> Project

    Visual C++
      -> Win32
        -> Win32 Console Application


Change the ARCH in the main Dialog to "x64" and the Configuration to "Release"
(or to match the parameters to cmake).

Replace the empty main with a libxlsxwriter example from the distro. Make sure
to include "stdafx.h" and "xlsxwriter.h":

@code
#include "stdafx.h" // This may not be required.

#include "xlsxwriter.h"

int main() {

    lxw_workbook  *workbook = workbook_new("hello_world.xlsx");
    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);

    worksheet_write_string(worksheet, 0, 0, "Hello", NULL);
    worksheet_write_number(worksheet, 1, 0, 123, NULL);

    workbook_close(workbook);

    return 0;
}
@endcode

Edit the application properties:

    Project
      -> ConsoleApplication Properties

Set the libxlsxwriter include path to match the path used above:

    Configuration Properties
      -> C/C++
        -> General
          -> Additional Include Directories

    Set it to the following (or similar path used above):

    C:\Users\Username\tmp\install_dir\libxlsxwriter\include

Set the linker directories to match the path created above:

    Configuration Properties
      -> Linker
        -> General
          -> Additional Library Directories

    Add the following (or similar paths used above):

    C:\Users\Username\tmp\install_dir\libxlsxwriter\lib\x64\Release
    C:\Users\Username\tmp\install_dir\zlib\lib

Set the linker additional libraries to match the zlib and xlsxwriter libs
created above:

    Configuration Properties
      -> Linker
         -> Input
            -> Additional Dependencies

    Add the following:

    xlsxwriter.lib
    zlib.lib

Build the solution and run the output executable. It should create a
hello_world.xlsx file in the same directory you ran it from.


@subsection gsg_ming Installation on Windows using Mingw-w64 and MSYS2

The libxlsxwriter library can also be compiled on Windows using the
[Mingw-w64](http://mingw-w64.org/doku.php) "Minimalist GNU for Windows"
toolchain. These tools can be run from the Windows `cmd.exe` but it is
recommended to use the [MSYS2](http://msys2.github.io) "Minimal System" Bourne
Shell.

Here are some instructions on how to compile libxlsxwriter with Mingw-w64 and
MSYS2:

    # Install MSYS2 64 or 32 bit from http://msys2.github.io/

    # Install the dev tools for libxlsxwriter.
    pacman -S git gcc make zlib-devel

    # Clone and build libxlsxwriter.
    git clone https://github.com/jmcnamara/libxlsxwriter.git
    cd libxlsxwriter/
    make

By default the library is installed in `/usr/local` on MinGW/MSYS systems. If
you know how to extend your build environments to use that directory then you
can just run `make install`. However, it is generally causes less compile/link
issues if you install them in the `/usr` directory like this:

    make install PREFIX=/usr

After compilation you can follow the instructions in the @ref gsg_using
section above. When compiling with the library you may also need to link
against the zlib library using `-lz`:

    gcc myexcel.c -o myexcel -lxlsxwriter -lz

It is also possible to use [Cygwin](https://cygwin.com) and the older [MinGW
and MSYS](http://mingw.org). Libxlsxwriter has been confirmed to compile and
work in all of these environments.

See also @ref gsg_tmpdir.

@subsection gsg_qt Installation in Qt-Creator for Windows

The following external guide shows how to [Build libxlsxwriter inside
Qt-Creator for Windows](https://github.com/jmcnamara/libxlsxwriter/issues/270)
with step by step instructions.

@section gsg_bsd Installation on FreeBSD and OpenBSD

Installation on FreeBSD and OpenBSD is mainly the same as on @ref gsg_linux
"Linux". To compile the library @ref gsg_git "get the source code" and build it
using **gmake** (not make):

    cd libxlsxwriter
    gmake

Then follow the instructions in the Linux section to @ref gsg_install
"install" and @ref gsg_using "use" the library.

Both FreeBSD and OpenBSD come with the zlib development libraries
pre-installed so there are no additional dependencies. However, if you have
any issues then follow the instructions to @ref gsg_dependencies "install zlib".


@section gsg_compilation_options Compilation Options

As shown in the previous sections Libxlsxwriter provides both a Make and
CMake based build system. The Make build is a straightforward system for
building the library and running tests on Unix like systems. The CMake system
offers support for more operating systems, cross compilation, and integration
with larger CMake builds. In particular it enables building on Windows.

The following are various compilation targets and options for both build systems:

| Make                     | CMake                                      | Description                                               |
| :----------------------- | :----------------------------------------- | :-------------------------------------------------------- |
| `examples`               | `-DBUILD_EXAMPLES=ON`                      | Build the example                                         |
| `test`                   | `-DBUILD_TESTS=ON`                         | Build the tests                                           |
| `USE_DTOA_LIBRARY=1`     | `-DUSE_DTOA_LIBRARY=ON`                    | Use alternative double in sprintf                         |
| `USE_MEM_FILE=1`         | `-DUSE_MEM_FILE=ON`                        | Use `fmemopen()`/`open_memstream()` instead of temp files |
| `USE_OPENSSL_MD5=1`      | `-DUSE_OPENSSL_MD5=ON`                     | Use OpenSSL for MD5 digest                                |
| `USE_NO_MD5=1`           | `-DUSE_NO_MD5=ON`                          | Don't use a MD5 digest                                    |
| `USE_SYSTEM_MINIZIP=1`   | `-DUSE_SYSTEM_MINIZIP=ON`                  | Use system minzip library                                 |
| `USE_STANDARD_TMPFILE=1` | `-DUSE_STANDARD_TMPFILE=ON`                | Use system `tmpfile()` function                           |
| `USE_BIG_ENDIAN=1`       | `-DUSE_BIG_ENDIAN=ON`                      | Build on big endian systems                               |
| `universal_binary`       | `-DCMAKE_OSX_ARCHITECTURES="x86_64;arm64"` | Create a macOS "Universal Binary"                         |
|                          | `-DBUILD_SHARED_LIBS=ON`                   | Build shared library (default on)                         |
|                          | `-DUSE_STATIC_MSVC_RUNTIME=ON`             | Use static msvc runtime library                           |
|                          | `-DCMAKE_BUILD_TYPE=Release`               | Set the build type.                                       |


The compilation options would be used as follows:

    # Make
    make examples USE_DTOA_LIBRARY=1

    # CMake
    mkdir build
    cd build
    cmake .. -DCMAKE_BUILD_TYPE=Release -DBUILD_EXAMPLES=ON -DUSE_DTOA_LIBRARY=ON
    cmake --build . --config Release

Each of the options are explained below:

- `examples/BUILD_EXAMPLES`: Builds the @ref examples "example programs".

- `test/BUILD_TESTS`: Builds the tests (see @ref running_the_tests). With Make
  the tests are also run once they are compiled. With CMake you can run them
  using `ctest`.

- `USE_DTOA_LIBRARY`: See @ref gsg_dtoa "using a double formatting library".

- `USE_MEM_FILE`: Use fmemopen()/open_memstream() instead of temporary files.
  This option isn't on by default since it isn't supported on Windows.

- `USE_OPENSSL_MD5`: Uses OpenSSL to provide a MD5 digest of image files in
  order to avoid storing duplicates. See @ref gsg_md5.

- `USE_NO_MD5`: Don't use a MD5 digest of image files in order to remove
  duplicates. This can be used if you aren't handling image files and don't
  need the additional function in the library. See @ref gsg_md5.

- `USE_SYSTEM_MINIZIP`: Uses a system minizip library, rather than the
  included copy, to create the xlsx zip container. See @ref gsg_minizip.

- `USE_STANDARD_TMPFILE`: Uses the standard library `tmpfile()` function
  to handle temp files instead of `tmpfileplus`. See @ref gsg_tmpdir.

- `USE_BIG_ENDIAN`: Compiles libxlsxwriter on a big endian system. See @ref
  gsg_endian.

- `universal_binary/CMAKE_OSX_ARCHITECTURES`: Builds a "universal binary" for
   both Apple silicon and Intel-based Macs. See @ref gsg_universal.

- `BUILD_SHARED_LIBS`: Builds a dynamically loading version of the library
  (`.so`, `.dll` or `.dylib` depending on the operating system).

- `USE_STATIC_MSVC_RUNTIME`: Sets flags for Microsoft Visual C to use a static
  MSVC runtime.

- `CMAKE_BUILD_TYPE`: Sets the build type (generally `Release` or `Debug`).

You can view, and set, your CMake options from within your build directory
using the `ccmake` tool:

    ccmake .


@subsection gsg_dtoa Using a double formatting library

Excel uses an IEEE 754 doubles for all numeric values. These values are stored
in standard `sprintf(...,"%.16G",...)` formatting as numbers like "1234.56" or
"456E+123". However in some locales, such as "de_DE" these numbers can be
stored with the locale specific decimal place like "1234,56" which causes
Excel to give an error when it loads the file.

It some cases this issue can be resolved by using the `setlocale()` or
`uselocale()` functions in your application. Alternatively you can compile
libxlsxwriter with support for a third party `dtoa()` (decimal to ascii)
function. Currently libxlsxwriter uses the [Milo Yip DTOA
library](https://github.com/miloyip/dtoa-benchmark) as an optional
compilation. This avoids the locale sprintf issue and it is also 40-50% faster
than the standard dtoa for raw numeric data.


@subsection gsg_md5 MD5 functionality for handling duplicate images

Libxlsxwriter uses a an MD5 digest to avoid including duplicate image files in
the xlsx file. By default it uses a third party library, [Openwall
MD5](https://openwall.info/wiki/people/solar/software/public-domain-source-code/md5),
which is a fast portable implementation of the MD5 Algorithm and which uses
the same function prototypes as OpenSSL MD5 digest. See @ref license.

The Openwall MD5 code is included in the libxlsxwriter repo and compiled in by
default. If you don't want to use this code, and the additional license, you
can use OpenSSL's MD5 functions dynamically by using the `USE_OPENSSL_MD5`
option:

    make USE_OPENSSL_MD5=1

    # or:
    cmake .. -DUSE_OPENSSL_MD5=ON

This requires that you have the OpenSSL development libraries installed and on
paths known to your compiler.

If this MD5 functionality isn't required it is possible to compile
libxlsxwriter without image de-duplication by using the `USE_NO_MD5=1` option:

    make USE_NO_MD5=1

    # or:
    cmake .. -DUSE_NO_MD5=ON

@subsection gsg_minizip Linking against system minizip

Libxlsxwriter uses the `minizip` component of [Zlib](http://www.zlib.net) to
create the xlsx zip file container. The source files for `minizip` are
included in the src tree of libxlsxwriter and are statically linked by
default.

If you have a `lminizip` library already installed on your system and prefer
to dynamically link against that you can use the following compilation option:

    make USE_SYSTEM_MINIZIP=1

    # or:
    cmake .. -DUSE_SYSTEM_MINIZIP=ON


@subsection gsg_tmpdir Specifying a TEMP directory for libxlsxwriter

The libxlsxwriter library creates temporary files in the system `TEMP`
directory during assembly of an xlsx file. On Windows this directory may not
be writeable by a libxlsxwriter application (although it will try several
`TEMP` locations before returning an error). To work around this you can set
the `tmpdir` parameter of the #lxw_workbook_options struct and pass it to
`workbook_new_opt()`:

@code
   lxw_workbook_options options = {.constant_memory = LXW_FALSE,
                                   .tmpdir = "C:\\Temp"};

   lxw_workbook  *workbook  = workbook_new_opt("filename.xlsx", &options);
@endcode

This can also be used on Unix systems where the `TEMP` directory isn't
writeable.

The TEMP file handling with optional temporary directory support is provided
by the
[Tmpfileplus](http://www.di-mgt.com.au/c_function_to_create_temp_file.html)
library which is included in the source tree. If you wish to use the standard
library `tmpfile()` function instead you can compile without `tmpfileplus` as
follows:

    make USE_STANDARD_TMPFILE=1

    # or:
    cmake .. -DUSE_STANDARD_TMPFILE=ON

@note When using the the standard library `tmpfile()` the `tmpdir` parameter,
shown above, is ignored.

@subsection gsg_endian Compiling on Big Endian Architecture

Libxlsxwriter can be compiled on a big endian system as follows:

    make USE_BIG_ENDIAN=1

    # or:
    cmake .. -DUSE_BIG_ENDIAN=ON

@subsection gsg_universal Compiling a universal binary on macOS

With Xcode 12.2 and later you can compile libxlsxwriter as a "universal
binary" for both Apple silicon and Intel-based Macs, i.e., arm64 and x86_64.

You can compile a universal binary with standard make as follows:

    $ make universal_binary

    # Which gives:
    $ lipo -archs lib/libxlsxwriter.a
    x86_64 arm64

    $ lipo -archs lib/libxlsxwriter.dylib
    x86_64 arm64

Or with CMake:

    mkdir build
    cd build
    cmake .. -DCMAKE_OSX_ARCHITECTURES="x86_64;arm64"
    make


@subsection gsg_minimal Minimal dependency compilation

As explained in the previous sections Libxlsxwriter includes 3 additional
libraries within the `third_party` directory:

1. `md5`: Used for MD5 hashing to avoid including duplicate images. See @ref
   gsg_md5.

2. `minizip`: Uses creating the xlsx zip container (this is part of the zlib
   code base but generally packaged separately). See @ref gsg_minizip.

3. `tmpfileplus`: Used mainly to overcome temp file issues on Windows but also
   used for changing the default temp directory. See @ref gsg_tmpdir.

These components are included in the libxlsxwriter repository to ensure that
the library compiles and runs on as many OSes as possible with the least
amount of additional dependencies.

However, all of these are optional and a minimal version of libxlsxwriter can
be compiled without them by relying on external libraries as follows:

    # Make:
    make USE_OPENSSL_MD5=1 USE_SYSTEM_MINIZIP=1 USE_STANDARD_TMPFILE=1

    # CMake:
    mkdir build
    cd build
    cmake .. -DUSE_OPENSSL_MD5=ON -DUSE_SYSTEM_MINIZIP=ON -DUSE_STANDARD_TMPFILE=ON
    cmake --build .

@section gsg_next Next steps

Once you get libxlsxwriter built and working the next sections will show you
how to create some more in-depth examples.


Next: @ref tutorial01


*/