C++ Considerations for Cross-Platform Applications
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Contents |
Stack Alignment Issue on OS X
For OS X applications, all memory data must be stack-aligned on 16-byte boundaries:
- For details, see Eli Boling's blog: http://blogs.embarcadero.com/eboling/2009/05/20/5607.
- Also see the ALIGN_STACK Define in Conditional compilation (Delphi).
Available C/C++ Header Files
RAD Studio provides separate C/C++ header files for different target platforms. These files are located in the $(BDS)\include standard search path.
To use header files from a remote search path, see Add Remote Path Item or Edit Remote Path Item. For example, on OS X you can add the OpenGL and GLUT libraries, as described in the code example OpenGL Multicolor Tetrahedron (C++). The Platform Assistant Client copies automatically the files from remote paths to the development system. (You must have installed the Platform Assistant Server on the remote system.)
For Mac OS X
The header files for Mac OS X are located on the development PC in $(BDS)\include\osx.
Sub-directory in $(BDS)\include\osx
|
Description |
|---|---|
\crtl
|
C/C++ RTL header files (.h). Some of these files include the C/C++ header files located on Mac in the /usr/include directory. For more information see OS X C RTL.
|
\rtl
|
Delphi RTL machine generated header files (.hpp). |
For Win32
The header files for Win32 are located in $(BDS)\include\windows. The Win64 target platform is not supported by C++Builder.
Subdirectory in $(BDS)\include\windows
|
Description |
|---|---|
\crtl
|
C/C++ RTL header files (.h). For more information see C Runtime Library Reference Index. |
\fmx
|
FireMonkey machine generated header files (.hpp) |
\rtl
|
Delphi RTL machine generated header files (.hpp) |
\sdk
|
Microsoft Windows SDK header files (.h) |
\vcl
|
VCL machine generated header files (.h and .hpp) |
Framework Availability on Different Platforms
VCL
The VCL supports development on Windows only (both 32-bit and 64-bit). (C++Builder does not support 64-bit Windows yet.)
FireMonkey
The FireMonkey or FMX framework is supported on Mac OS X, 32-bit Windows, and 64-bit Windows. (C++Builder does not support 64-bit Windows yet.)
Delphi RTL (different from the C/C++ RTL)
The Delphi run-time library is supported on Mac OS X, 32-bit Windows, and 64-bit Windows. (C++Builder does not support 64-bit Windows yet.)
Using Frameworks on the OS X Platform
The BCCOSX and XLINK options related to Mac frameworks are described in the following table:
| Tool | Option | Description |
|---|---|---|
| BCCOSX | --sysroot
|
When the linker is invoked, this option is converted to the -Fr option.
|
| BCCOSX | --framework
|
When the linker is invoked, this option is converted to the -Ff option.
|
| XLINK | -Fr
|
Specifies the location of the logical root directory. The logical root directory is a directory on the local (Windows) machine that represents the root of the remote (Mac OS X) machine. |
| XLINK | -Fp
|
Specifies the remote library paths. Also see the -L option.
|
| XLINK | -Ff
|
Instructs the linker to link the specified framework. For more information, see the --framework documentation.
|
For a description of how to instruct BCCOSX and XLINK to link to Mac frameworks, see --framework.
For more information on Mac frameworks, see Mac OS X Application Development#Using Frameworks in Mac Apps.
String Literals char16_t and wchar_t on the OS X Platform
On Mac OS X, char16_t is not equivalent to wchar_t (as it is on Windows):
- On Windows,
wchar_tandchar16_tare both double-byte characters. - On Mac, however, a
wchar_tis a 4-byte character.
So, to declare UTF-16 constant strings, on Windows use either the L or the u prefix, whereas on Mac use the u prefix.
Example on Windows:
UnicodeString(L"Text"), UnicodeString(u"Text")
Example on Mac:
UnicodeString(u"Text")
Using the L prefix for string literals on Mac OS X is not, however, wrong. In this case, UTF-32 constant strings are converted to UTF-16 strings.
For portability, use the _D macro to write constant strings that are prefixed accordingly with L or u. Example:
UnicodeString(_D("Text"))
Inline Assembly Restriction
You can write IA-32 (including SSE4.2) inline assembly in C++ code for OS X, but you cannot compile C++ code to assembly.