How to change the amount of building threads in Xcode?

c++ multithreading xcode compilation building
Dries Staelens picture Dries Staelens · Dec 3, 2010 · Viewed 17.9k times · Source

I'm building a couple of C++ files in xcode that take a lot of memory to compile (+1 GB / file). Because I do this on my dual core laptop, xcode uses 2 threads for building. The two threads will eventually be building the files that take a lot of memory simultaneously so the system suffers memory starvation and the compilation grinds to a near halt.

A sufficient solution for me would be to force Xcode to use only one build thread. Does anybody know a way to change how many build threads Xcode uses?

For those who are interested, the C++ files contain a sizable boost::spirit::qi parser.

Answer

user405725 picture user405725 · Dec 3, 2010

The number of threads Xcode is using to perform tasks is controlled by PBXNumberOfParallelBuildSubtasks option. You can change it with the following command: - defaults write com.apple.Xcode <key> <value>. For example:

defaults write com.apple.Xcode PBXNumberOfParallelBuildSubtasks 8

See Xcode User Defaults for more details.

There are also many other ways to speed up a compilation, from precompiled headers to distributed builds. Read Reducing Build Times for more information on this.

Good luck!

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