How to add pre-build step in qmake/qtcreator?

Question

I want the compiled application to have the commit number, source files checksums and other things to be available during the compilation.

In plain Makefiles I do like this:

prog: VERSION source.c
    gcc -DVERSION=\"$(shell cat VERSION)\" source.c -o prog 

VERSION: .git
    git describe > VERSION

How to use something similar with qmake?

Morea

Answer 1

If you were to pass the version information as an included file (let's say "version.h") instead of a #define, then you could add the following to your qmake file

# Define how to create version.h
version.target = version.h
version.commands = <PUT_YOUR_COMMANDS_HERE>
version.depends = .git

QMAKE_EXTRA_TARGETS += version

PRE_TARGETDEPS += version.h

The first 3 lines tell how to make a new target object called "version" that generates "version.h". It is made by executing the commands "<PUT_YOUR_COMMANDS_HERE>". The target is dependent on ".git"

The "QMAKE_EXTRA_TARGETS" says there is a new target known as "version".

The "PRE_TARGETDEPS" indicates that "version.h" needs to exist before anything else can be done (which forces it to be made if it isn't already made).

Greatgrandaunt

Trying to get this to work, having other issue: #5193214 – Morea

Unfortunately PRE_TARGETDEPS only puts the target at the front of the dependency list of the final target. Thus as soon as you compile in parallel runing make -j this is likely to fail. – Memorabilia

Answer 2

A simpler solution even if @jwernemy as nice way to solve it:

VERSION = $$system(-git-dir=$PWD/.git <PUT_YOUR_GIT_COMMANDS_HERE>)

Nonreturnable

In what directory will the command run? In source directory or in build directory? – Morea

And the .git is in the source directory. – Morea

you can use git --git-dir to specify the .git folder – Nonreturnable

like that git --git-dir=$PWD/.git <YOU_COMMANDS_HERE – Nonreturnable