C++11 simple lambda predicate syntax sample

I have done a simple sample how to use a C++11 lambda expression as predicate for a particular algorithm.


pred1 demonstrates the result type of a lambda expression is a function pointer.
pred2 demonstrates how to shorten the lengthy type declaration.

Conditional type selection using C++ template specializations

One of the very basic techniques of C++ meta-programming is to provide simple selector classes that provide to refer to a type from a (public) typedef member.

The basic pattern for type selections based on a condition applied to the template parameters passed, or even independently looks like the following code demonstrates:

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A compiled and running example of the above code can be found here.

Building GCC ARM cross toolchain on Suse Linux

I needed to have a GCC 4.7.1 toolchain for ARM (Cortex-M3) with the C++11 standard features.
So I tried following another blog post to compile the toolchain myself. Though, modifications were necessary, here's what to do step by step:

1. Ensure to have the necessary headers & libraries installed
I have used YAST's 'Install Software' feature, to install the following packages that will be necessary to complete all the build steps (just search for the package names, select and accept):

• gmp-devel
• mpfr-devel
• mpc-devel
• texinfo
• ncurses-devel
• termcap

2. Create a directory skeleton

    cd ~
    mkdir arm-none-eabi arm-none-eabi-src
    cd arm-none-eabi
    mkdir src build
    cd ~/arm-none-eabi-src
    mkdir src build

3. Download the the source packages and extract them

    cd ~/arm-none-eabi-src/src

    wget ftp://ftp.gnu.org/gnu/gcc/gcc-4.7.1/gcc-4.7.1.tar.bz2
    wget ftp://ftp.gnu.org/gnu/binutils/binutils-2.22.tar.bz2
    wget ftp://ftp.gnu.org/gnu/gdb/gdb-7.4.tar.bz2
    wget ftp://sources.redhat.com/pub/newlib/newlib-1.20.0.tar.gz

    tar -xf gcc-4.7.1.tar.bz2
    tar -xf binutils-2.22.tar.bz2
    tar -xf gdb-7.4.tar.bz2
    tar -xf newlib-1.20.0.tar.gz

4. Build the binutils

    cd ~/arm-none-eabi-src/build
    mkdir binutils-2.22
    cd binutils-2.22
    ../../src/binutils-2.22/configure \
      --target=arm-none-eabi \
      --prefix=$HOME/arm-none-eabi \
      --with-cpu=cortex-m3 \
      --with-no-thumb-interwork \
      --with-mode=thumb
    make all install
    export PATH="$PATH:$HOME/arm-none-eabi/bin"

5. Build GCC (Part1)

    cd ~/arm-none-eabi-src/build
    mkdir gcc-4.7.1
    cd gcc-4.7.1
    ../../src/gcc-4.7.1/configure --target=arm-none-eabi \
      --prefix=$HOME/arm-none-eabi --with-cpu=cortex-m3 \
      --with-mode=thumb --disable-multilib \
      --with-no-thumb-interwork \
      --enable-languages="c,c++" --with-newlib \
      --with-headers=../../src/newlib-1.20.0/newlib/libc/include
    make all-gcc install-gcc

The --enable-cxx-flags configure option might be additionally used to control the build flags of the libstdc++ (included in this step):

    --enable-cxx-flags='-fno-exceptions \
        -ffunction-sections -fno-omit-frame-pointer'

In general the same C++ compile flags should be used as they'll appear when building the intended target code.

6. Build GCC newlib with the cross compiler (Part2)

    cd ~/arm-none-eabi-src/build
    mkdir newlib-1.20.0
    cd newlib-1.20.0
    ../../src/newlib-1.20.0/configure --target=arm-none-eabi \
      --prefix=$HOME/arm-none-eabi --disable-multilib \
      --disable-newlib-supplied-syscalls
    make all install

A note about the --disable-newlib-supplied-syscalls option:
Disabling the default newlib syscall stub implementation is generally a good idea when you intend to compile for targets without using a linux like operating system, or no OS at all. It will leave you with linker errors on unimplemented stub functions you'll need to provide for newlib.
Removing the option will still enable you to override the newlib provided stubs with your own implementations.

Though, when you plan to use the cross-toolchain in conjunction with CMake, you should omit this option. CMake does some basic tests using the specified compiler definitions (e.g. from a toolchain.cmake file), that'll fail without the default stub implementations supplied.

7. Complete installing GCC

    cd ~/arm-none-eabi-src/build/gcc-4.7.1
    make all install

8. Build GDB

    cd ~/arm-none-eabi-src/build
    mkdir gdb-7.4
    cd gdb-7.4
    ../../src/gdb-7.4/configure --target=arm-none-eabi \
      --prefix=$HOME/arm-none-eabi
    make all install

UPDATE
The same works pretty well for GCC 4.8.2 also.