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Overview

Different platforms have minor differences in their implementations of c/c++. The most obvious of these is integer representations (e.g. 16/32/64 bit types). This package uses cmake detection scripts to check your platform's implementation and define some cross platform macros, types and classes that facilitate easy handling of these fundamental properties.

Major platform support includes posix/apple and mingw/msvc (partial).

Compiling & Linking

Include the following at the top of any translation unit that utilises the configuration definitions and tools.

   1 #include <ecl/config.hpp>
   2 
   3 // Functions
   4 using ecl::is_big_endian;
   5 using ecl::is_char_signed;
   6 
   7 // Types - refer to ecl/config/portable_types.hpp
   8 using ecl::int8;
   9 using ecl::uint8;
  10 // ...
  11 

Under the Hood

CMake can do the hard yards on most platforms/toolchains and autodetect what variables and headers can be used - this works mostly for the main platforms as outlined above. The result of this guesswork are a suite of macros stored in the ecl/config/ecl.hpp header. All macros are prefixed by an ECL, e.g. ECL_IS_POSIX.

When autodetection fails (you have a very embedded board, or your toolchain has been patched together in a very non-standard way) there is provision to manually supply details via the ECL_IS_CUSTOM macro. Refer to the custom platform detection tutorial.

Note that other packages also do some platform detection to varying degrees, e.g ecl_time_lite. The macros defined here are the most general purpose macros only.

Reference

Macros

// Platform macros - automatically detected by the build.
- ECL_IS_POSIX || ECL_IS_WIN32 || ECL_IS_APPLE || ECL_IS_CUSTOM
- ECL_HAS_POSIX_THREADS || ECL_HAS_WIN32_THREADS
- ECL_SIZE_OF_CHAR
- ECL_SIZE_OF_SHORT
- ECL_SIZE_OF_INT
- ECL_SIZE_OF_LONG
- ECL_SIZE_OF_LONG_LONG
- ECL_SIZE_OF_FLOAT
- ECL_SIZE_OF_DOUBLE
- ECL_SIZE_OF_LONG_DOUBLE
- ECL_CHAR_IS_SIGNED || ECL_CHAR_IS_UNSIGNED
- ECL_HAS_SHARED_LIBS || ECL_HAS_STATIC_LIBS
// ECL Development macros
- ECL_DISABLE_EXCEPTIONS
- ECL_DONT_INLINE
- ECL_DEPRECATED
- ECL_PUBLIC || ECL_LOCAL

Note that you may predefine ECL_HAS_SHARED_LIBS or ECL_HAS_STATIC_LIBS for your project if both are available and you want to force appropriate behaviour for the target set you are linking against.

Types

When you absolutely need to specify the bit-width type you need to use, the following typedefs are defined by the ECL when the appropriate types are available.

- ecl::int8,  ecl::uint8
- ecl::int16, ecl::uint16
- ecl::int32, ecl::uint32
- ecl::int64, ecl::uint64
- ecl::float32
- ecl::float64 
- ecl::float96 
- ecl::float128

Platform Sniffers

Checking for endianness:

// The function operates like a macro, and a good compiler will compile
// out the if mechanism and leave behind the required section of code.
if ( ecl::is_big_endian() {
    // ...
}

To check if your default char type is signed, or otherwise, use the following. Note that this only works for runtime checks. To do compile time checks (for use in template parameters etc), there is the ECL_CHAR_IS_SIGNED and ECL_CHAR_IS_UNSIGNED macros.

   1 if ( ecl::is_char_signed() {
   2    // ...
   3 }