Automatic Precompiled Header (PCH) file processing
--pch command-line option enables automatic PCH file processing.
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.
Automatic PCH file processing means that the compiler automatically looks for a qualifying PCH file, and reads it if found. Otherwise, the compiler creates one for use on a subsequent compilation.
When the compiler creates a PCH file, it takes the name of
the primary source file and replaces the suffix with .pch.
The PCH file is created in the directory of the primary source file
--pch_dir option is specified.