How do I utilise all the cores for nmake?

Question

I just got a new quad core computer and noticed that nmake is only using 1 process.

I used to use make which had the switch -j4 for launching 4 processes. What is the nmake equivalent?

[edit] Based on the information below I have been able to add a command to my qmake project file:

QMAKE_CXXFLAGS += /MP

Which effectively did it for me. Many thanks.

Answer 1

According to MSDN, there's no such option for nmake.

You can however make the compiler build multiple files in parallel by using the /MP option with the VC++ command line compiler and passing multiple files at the same time:

> cl /MP a.cpp b.cpp c.cpp

However note that most Makefiles don't call the compiler like this - they usual invoke the compiler separate for each individual source file, which would prevent the /MP option from doing anything useful.

Answer 2

Quick googling gives: http://msdn.microsoft.com/en-us/library/bb385193.aspx

Answer 3

Another generic, non-Qt-related way to tell nmake to use all the cores is to set environmental variable CL to /MP:

set CL=/MP
nmake

will use all the CPU cores.

Answer 4

The CMake 2.8.1 RC1, as for the time of writing this it's ready to try, does bring new generator for NMake which is called NMake Makefiles JOM and it generates NMake with specific settings for jom, which is the drop in replacement of NMake. Thus, it gives multi-processing enabled building using NMake.

Answer 5

This doesn't work for normal makefiles, but there is a setting in Visual Studio 2005 that lets you build more than one .vcproj file at the same time (provided one isn't dependent on the other). Tools -> Options -> Projects and Solutions -> Build and Run -> X maximum number of parallel project builds.

Answer 6

Incredibuild claims to be able to run nmake builds on multiple cores / multiple machines. I don't have any experience of it.