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libcares/INSTALL.md  view on Meta::CPAN

If you get your code off a Git repository rather than an official
release tarball, see the [GIT-INFO](GIT-INFO) file in the root directory
for specific instructions on how to proceed.

In particular, if not using CMake you will need to run `./buildconf` (Unix) or
`buildconf.bat` (Windows) to generate build files, and for the former
you will need a local installation of Autotools.  If using CMake the steps are
the same for both Git and official release tarballs.

AutoTools Build
===============

### General Information, works on most Unix Platforms (Linux, FreeBSD, etc)

A normal Unix installation is made in three or four steps (after you've
unpacked the source archive):

    ./configure
    make
    make ahost adig acountry (optional)
    make install

You probably need to be root when doing the last command.

If you have checked out the sources from the git repository, read the
[GIT-INFO](GIT_INFO) on how to proceed.

Get a full listing of all available configure options by invoking it like:

    ./configure --help

If you want to install c-ares in a different file hierarchy than /usr/local,
you need to specify that already when running configure:

    ./configure --prefix=/path/to/c-ares/tree

If you happen to have write permission in that directory, you can do `make
install` without being root. An example of this would be to make a local
install in your own home directory:

    ./configure --prefix=$HOME
    make
    make install

### More Options

To force configure to use the standard cc compiler if both cc and gcc are
present, run configure like

    CC=cc ./configure
    # or
    env CC=cc ./configure

To force a static library compile, disable the shared library creation
by running configure like:

    ./configure --disable-shared

If you're a c-ares developer and use gcc, you might want to enable more
debug options with the `--enable-debug` option.

### Special Cases

Some versions of uClibc require configuring with `CPPFLAGS=-D_GNU_SOURCE=1`
to get correct large file support.

The Open Watcom C compiler on Linux requires configuring with the variables:

    ./configure CC=owcc AR="$WATCOM/binl/wlib" AR_FLAGS=-q \
        RANLIB=/bin/true STRIP="$WATCOM/binl/wstrip" CFLAGS=-Wextra


### CROSS COMPILE

(This section was graciously brought to us by Jim Duey, with additions by
Dan Fandrich)

Download and unpack the c-ares package.

`cd` to the new directory. (e.g. `cd c-ares-1.7.6`)

Set environment variables to point to the cross-compile toolchain and call
configure with any options you need.  Be sure and specify the `--host` and
`--build` parameters at configuration time.  The following script is an
example of cross-compiling for the IBM 405GP PowerPC processor using the
toolchain from MonteVista for Hardhat Linux.

```sh
#! /bin/sh

export PATH=$PATH:/opt/hardhat/devkit/ppc/405/bin
export CPPFLAGS="-I/opt/hardhat/devkit/ppc/405/target/usr/include"
export AR=ppc_405-ar
export AS=ppc_405-as
export LD=ppc_405-ld
export RANLIB=ppc_405-ranlib
export CC=ppc_405-gcc
export NM=ppc_405-nm

./configure --target=powerpc-hardhat-linux \
     --host=powerpc-hardhat-linux \
     --build=i586-pc-linux-gnu \
     --prefix=/opt/hardhat/devkit/ppc/405/target/usr/local \
     --exec-prefix=/usr/local
```

You may also need to provide a parameter like `--with-random=/dev/urandom`
to configure as it cannot detect the presence of a random number
generating device for a target system.  The `--prefix` parameter
specifies where c-ares will be installed.  If `configure` completes
successfully, do `make` and `make install` as usual.

In some cases, you may be able to simplify the above commands to as
little as:

    ./configure --host=ARCH-OS


### Cygwin (Windows)

libcares/INSTALL.md  view on Meta::CPAN

```sh
cd /path/to/cmake/source
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local/cares -G "Ninja" ..
ninja
sudo ninja install
```

Windows MSVC Command Line
-------------------------

```
cd \path\to\cmake\source
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=C:\cares -G "NMake Makefiles" ..
nmake
nmake install
```

Windows MinGW-w64 Command Line via MSYS
---------------------------------------
```
cd \path\to\cmake\source
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=C:\cares -G "MSYS Makefiles" ..
make
make install
```


Platform-specific build systems
===============================

Win32
-----

### Building Windows DLLs and C run-time (CRT) linkage issues

As a general rule, building a DLL with static CRT linkage is highly
discouraged, and intermixing CRTs in the same app is something to
avoid at any cost.

Reading and comprehension of Microsoft Knowledge Base articles
KB94248 and KB140584 is a must for any Windows developer. Especially
important is full understanding if you are not going to follow the
advice given above.

 - [KB94248](http://support.microsoft.com/kb/94248/en-us) - How To Use the C Run-Time

 - [KB140584](http://support.microsoft.com/kb/140584/en-us) - How to link with the correct C Run-Time (CRT) library

 - [KB190799](http://msdn.microsoft.com/en-us/library/ms235460) - Potential Errors Passing CRT Objects Across DLL Boundaries

If your app is misbehaving in some strange way, or it is suffering
from memory corruption, before asking for further help, please try
first to rebuild every single library your app uses as well as your
app using the debug multithreaded dynamic C runtime.


### MingW32

Make sure that MinGW32's bin dir is in the search path, for example:

    set PATH=c:\mingw32\bin;%PATH%

then run 'make -f Makefile.m32' in the root dir.


### MSVC 6 caveats

If you use MSVC 6 it is required that you use the February 2003 edition PSDK:
http://www.microsoft.com/msdownload/platformsdk/sdkupdate/psdk-full.htm


### MSVC from command line

Run the `vcvars32.bat` file to get a proper environment. The
`vcvars32.bat` file is part of the Microsoft development environment and
you may find it in `C:\Program Files\Microsoft Visual Studio\vc98\bin`
provided that you installed Visual C/C++ 6 in the default directory.

Further details in [README.msvc](README.msvc)


### MSVC IDEs

Details in [README.msvc](README.msvc)


### Important static c-ares usage note

When building an application that uses the static c-ares library, you must
add `-DCARES_STATICLIB` to your `CFLAGS`.  Otherwise the linker will look for
dynamic import symbols.


IBM OS/2
--------

Building under OS/2 is not much different from building under unix.
You need:

  - emx 0.9d
  - GNU make
  - GNU patch
  - ksh
  - GNU bison
  - GNU file utilities
  - GNU sed
  - autoconf 2.13

If during the linking you get an error about `_errno` being an undefined
symbol referenced from the text segment, you need to add `-D__ST_MT_ERRNO__`
in your definitions.

If you're getting huge binaries, probably your makefiles have the `-g` in
`CFLAGS`.