Precompiled Headers Command Line Options for Clang-enhanced C++ Compilers

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Precompiled header files can dramatically increase compilation speed by storing an image of the symbol table on disk in a file, then later reloading that file from disk instead of parsing all the header files again. Directly loading the symbol table from disk is much faster than parsing the text of header files, especially if several source files include the same header file.

To use precompiled header files on the command line, use the following options in your Clang-enhanced C++ compiler command.

Precompiled Header Options:

Compiler Option	Description	Details	Example
-emit-pch	Generates a PCH file	Option used to generate a new precompiled header file.	<compiler> -emit-pch -o PCHfile.pch TestPCH.h
-include-pch	Includes a PCH file	Option that can be used to includes a PCH file in a C++ source file.	<compiler> -emit-obj -include-pch PCHfile.pch SourceFile.cpp

See Also

• C++ Compiler Precompiled Headers (Project Options page for PCH options)
• Using Precompiled Headers with Clang-enhanced C++ Compilers
• Precompiled Headers Overview
• Precompiled Header Wizard
• Precompiled Headers Command Line Options for BCC32