build_always

meson.build

#                                                -*- Mode: python; python-indent-offset: 2 -*-

project ('test always_build', 'c')

buildid_h = custom_target ('buildid.h',
	                   output : 'buildid.h',
                           command : ['../mkbuildid.sh', '+"%M"'],
                           build_always : true)

executable ('tester', 'tester.c', buildid_h)

mkbuildid.sh

#!/bin/sh
set -e

BUILDID="$(date '+"%M"')"

test ! -e buildid.h ||
    test "$(echo $BUILDID)" != "$(cat buildid.h)" ||
    exit 0

echo $BUILDID > buildid.h

tester.c

#include <stdio.h>
#include <stdint.h>

static const char *buildid =
#include "buildid.h"
  ;

int
main (int argc, char *argv[])
{
  printf ("buildid: %s\n", buildid);
  return 0;
}
// g++ -Wall -O2 -std=gnu++11 -fdiagnostics-color x.cc && ./a.out