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If you don't know it, CMake can use ninja instead of make for compilation so instead of "mkdir build && cd build && cmake .. && make" you can run "mkdir build &

If you don't know it, CMake can use ninja instead of make for compilation so instead of "mkdir build && cd build && cmake .. && make" you can run "mkdir build && cd build && cmake -GNinja && ninja". It feels faster on my side projects (haven't benchmarked it really), but most importantly, when running a parallel build it does not interleave the output of the different steps, making it much easier to read warnings and errors.

jart 6y ago
If anyone wants to know more about preventing interleaving, try using `make -O` or adding `GNUMAKEFLAGS += --output-sync` to the top of your Makefile.
ihnorton 6y ago
A small warning for code with many CMake ExternalProject dependencies: the defaults for cmake+ninja will recursively run `ninja -jN` for each level of the dependency tree, which can spawn a very large number of compile jobs. There is a proposal to add jobserver support for global process count management [1], but it has not been merged for philosophical reasons (IIRC). The CMake folks maintain a soft fork with this patch applied, available in the `ninja` package on PyPI and probably elsewhere. [1] https://github.com/ninja-build/ninja/issues/1139 https://github.com/ninja-build/ninja/issues/1139
tomjakubowski 6y ago
Ninja is especially beneficial on large projects with lots of source files. Where Make can take 30+ seconds to run a "no-op" build, when nothing needs rebuilding, ninja does it instantly.
- kingosticks 6y ago
  The conclusion at https://david.rothlis.net/ninja-benchmark/ https://david.rothlis.net/ninja-benchmark/ (2016) was that this doesn't have an impact until you get to really large projects (assuming you are able to utilise make -j).
CUViper 6y ago
You can also use "cmake --build <dir>" to build regardless of which generator was used.
maccard 6y ago
For cross platform-ness you can do cmake -H. -Bbuild -GNinja cd build && ninja

jart 6y ago

If anyone wants to know more about preventing interleaving, try using `make -O` or adding `GNUMAKEFLAGS += --output-sync` to the top of your Makefile.

ihnorton 6y ago

A small warning for code with many CMake ExternalProject dependencies: the defaults for cmake+ninja will recursively run `ninja -jN` for each level of the dependency tree, which can spawn a very large number of compile jobs. There is a proposal to add jobserver support for global process count management [1], but it has not been merged for philosophical reasons (IIRC). The CMake folks maintain a soft fork with this patch applied, available in the `ninja` package on PyPI and probably elsewhere. [1] https://github.com/ninja-build/ninja/issues/1139 https://github.com/ninja-build/ninja/issues/1139

tomjakubowski 6y ago

Ninja is especially beneficial on large projects with lots of source files. Where Make can take 30+ seconds to run a "no-op" build, when nothing needs rebuilding, ninja does it instantly.

kingosticks 6y ago
The conclusion at https://david.rothlis.net/ninja-benchmark/ https://david.rothlis.net/ninja-benchmark/ (2016) was that this doesn't have an impact until you get to really large projects (assuming you are able to utilise make -j).

CUViper 6y ago

You can also use "cmake --build <dir>" to build regardless of which generator was used.

maccard 6y ago

For cross platform-ness you can do cmake -H. -Bbuild -GNinja cd build && ninja