vlmcsd-svn812-2015-08-30-Hotbird64

README.compile-and-pre-built-binaries

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+Compilation and pre-built binaries FAQ
+======================================
+
+What is the best pre-built binary for my system or device?
+----------------------------------------------------------
+
+None. The best binary is compiled by yourself using a toolchain that is
+optimized for your system or device in every respect.
+
+
+How do I compile my own binary?
+-------------------------------
+
+On a full blown desktop system this is relativly easy. If not already done so,
+install a C compiler (e.g. gcc or clang) through your packet manager, e.g.
+"sudo apt-get install gcc" (Debian/Ubuntu) or "sudo yum install gcc"
+(RedHat/Fedora).
+
+Then cd to your vlmcsd directory and type "make". vlmcs and vlmcsd will
+be built right away for your local system.
+
+If you installed gcc and it is not the default compiler for your OS or
+distribution, you may need to type "make CC=gcc" to explicitly select a
+specific C compiller.
+
+
+How do I compile a binary for my embedded device?
+-------------------------------------------------
+
+What you need is cross-compiling toolchain for your device. It consists of a
+C compiler, libraries, header files and some tools (called binutils). The
+toolchain must match the device in processor architecture, endianess, ABI,
+library and header files version, library configuration, ...
+
+If the endianess or ABI differs or the version of some library between
+toolchain and device differs too much, the resulting binary does not run
+on your device.
+
+Once you have a proper toolchain (probably found on the Internet for download),
+unpack it to any directory and type
+
+     "make CC=/path/to/toolchain/bindir/c-compiler-binary"
+
+Building vlmcsd for using a cross-compiling toolchain is as easy as building
+vlmcsd for your local machine. The only question is, whether this you have
+a toolchain that actually matches your device.
+
+Whenever you change any parameter of the make command line, you must "clean"
+the source directory from intermediate files and output from previous runs
+of make. You can do so by typeing "make clean" or force make to behave as if
+the directory were clean by adding -B to the command line, e.g.
+
+     "make -B CC=/path/to/toolchain/bindir/c-compiler-binary"
+
+
+I have downloaded several promising toolchains for my device but they all
+don't work. Can I create my own toolchain?
+-------------------------------------------------------------------------
+
+You can use tools like buildroot or OpenWRT. Both are able to create toolchains
+for many embedded devices. But this is out of the scope of this document.
+If you are unable to walk through thousands of configuration options and make
+the right choice, you may probably want to try the pre-built binaries.
+
+
+How to choose a pre-built binary?
+---------------------------------
+
+The directory structure for the binaries is
+
+binaries
++
++--<operating system>
+   +
+   +--<cpu arch>
+      +
+      +--<endianess> (omitted if CPU or OS does not allow multi-endianess)
+         +
+         +--<C-library>
+
+<C-library> can also be "static". That means no special library is required.
+Static binaries are much bigger and need more RAM than dynamic binaries but
+are more likely to run on your system. Use a static binary only, if none of
+the dynmic binaries run.
+
+Don't get confused when a binary is named after an OS or a specific device,
+e.g. the name contains "openwrt", "tomato" or "Fritzbox". This does not mean
+that the binary will run only on that OS or on that device. It is a hint only
+where I got or built the toolchain from.
+
+
+How to determine the endianess of my system?
+--------------------------------------------
+
+- All Intel CPUs (x86, x32, x64) are little-endian only
+- Windows is little-endian only even if the CPU support big-endian
+- big-endian ARM is extremely uncommon. You can safely assume little-endian
+- little-endian PowerPC virtually does not exist since only newer POWER7
+  and POWER8 CPUs support it. Always assume big-endian.
+- For MIPS both little-endian and big-endian are common. Most Broadcomm and
+  TI chips run little-endian. Most Atheros and Ikanos CPUs run big-endian.
+
+Try typing
+     echo -n I | od -o | awk 'FNR==1{ print substr($2,6,1)}'
+
+This returns 1 for little-endian systems and 0 for big-endian systems. However
+some devices do not have the od command and thus this method won't work.
+
+
+