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> I’d be interested in hearing about the problems Make has caused you The main problem that kept burning me was that I'd have a "dirty" build when I thought I

by umvi 7y ago

> I’d be interested in hearing about the problems Make has caused you The main problem that kept burning me was that I'd have a "dirty" build when I thought I had a clean one or an incorrect one when I thought I had a correct one. It was super hard to get the dependency graph correct because developers were creating files left and right but would only update the Makefile just enough to get it building (and forget to add new header files to the list of headers, etc) so I had little confidence in incremental builds and was always building from the ground up. CMake's generated build systems always have correct dependency graphs (i.e. it will only rebuild the bare minimum when you touch a given file) and I've always had complete confidence that my build is clean (since I just created a fresh directory) and that my incremental builds are correct.

kd5bjo 7y ago
That makes a lot of sense. Setting up automatic dependency detection is what finally made Make click for me, and it’s not the most straightforward process to get right. How does CMake detect the files that a given product depends on; does it have language-specific dependency detection or something else?
- umvi 7y ago
  > How does CMake detect the files that a given product depends on; does it have language-specific dependency detection or something else? Well actually, CMake is a build system generator - and the default build system it generates is Unix Makefiles. So I assume CMake generates Makefiles with the appropriate automatic dependency detection baked in, I'm not sure. The important part was that it eliminated human error on our team and we haven't had dependency graph problems since.
  - deng 7y ago
    CMake has its own dependency scanner for C/C++. Look for a file 'depend.make' and you'll see the header dependencies that CMake has detected, minus the headers that CMake thinks are system headers.
deng 7y ago
> and forget to add new header files to the list of headers This is why gcc/clang have the option to generate Makefiles for the header dependencies for you. Maintaining these yourself is a hopeless effort.

by umvi 7y ago

kd5bjo 7y ago

That makes a lot of sense. Setting up automatic dependency detection is what finally made Make click for me, and it’s not the most straightforward process to get right. How does CMake detect the files that a given product depends on; does it have language-specific dependency detection or something else?

umvi 7y ago
> How does CMake detect the files that a given product depends on; does it have language-specific dependency detection or something else? Well actually, CMake is a build system generator - and the default build system it generates is Unix Makefiles. So I assume CMake generates Makefiles with the appropriate automatic dependency detection baked in, I'm not sure. The important part was that it eliminated human error on our team and we haven't had dependency graph problems since.
- deng 7y ago
  CMake has its own dependency scanner for C/C++. Look for a file 'depend.make' and you'll see the header dependencies that CMake has detected, minus the headers that CMake thinks are system headers.

deng 7y ago

> and forget to add new header files to the list of headers This is why gcc/clang have the option to generate Makefiles for the header dependencies for you. Maintaining these yourself is a hopeless effort.