Support for Precompiled Header (PCH) files is
deprecated from ARM Compiler 5.05 onwards on all platforms. Note that ARM Compiler
on Windows 8 never supported PCH files.
PCH processing might not always be appropriate, for example,
where you have an arbitrary set of files with non-uniform initial
sequences of preprocessing directives.
The benefits of PCH processing occur when several source files
can share the same PCH file. The more sharing, the less disk space
is consumed. Sharing minimizes the disadvantage of large PCH files,
without giving up the advantage of a significant decrease in compilation
Therefore, to take full advantage of header file precompilation,
you might have to re-order the
of your source files, or group
within a commonly used header file.
Different environments and different projects might have differing
requirements. Be aware, however, that making the best use of PCH
support might require some experimentation and probably some minor
changes to source code.