Makefile under `An introduction to make` not rebuilding when included files are changed

[p-costa]

I hope this is worth opening an issue here.

In addition to fpm, I actually use the nice Makefile and dependencies generator under An introduction to make in some projects. The Makefile has a dependencies generator which parses Fortran sources to search for dependencies, also for included files, but does not re-build when these include files are changed.

See this example project:

$> tree
.
├── gen-deps.awk
├── Makefile
└── src
    ├── bla.f90
    ├── bla-inc.f90


$> cat src/bla.f90
module bla
  implicit none
  private

  public :: say_hello
contains
  subroutine say_hello
    include "bla-inc.f90"
    print *, "Hello, bla!"
  end subroutine say_hello
end module bla


$> cat src/bla-inc.f90
print*,'Hey!'

$> cat Makefile
(...)
# List of all source files
SRCS := src/bla.f90
TEST_SRCS :=
(...)

When I touch src/bla.f90, the project is correctly rebuilt, but not when I touch src/bla-inc.f90. Unfortunately, I'm not proficient enough with GNU make to fix this, but maybe someone can!

[awvwgk]

Looks like I'm resolving the included file too often, this seems like the appropriate fix to me:

diff --git a/learn/building_programs/project_make.md b/learn/building_programs/project_make.md
index fc2ede28..c3045bd6 100644
--- a/learn/building_programs/project_make.md
+++ b/learn/building_programs/project_make.md
@@ -262,7 +262,7 @@ $2 ~ /^["'].+["']$/ {
     # count included files per file to avoid having duplicates in our list
     if (incc[FILENAME,$2]++ == 0) {
         # Add the included file to our list, this might be case-sensitive
-        inc[++ii] = sprintf("$(%s) += $(%s)", FILENAME, $2)
+        inc[++ii] = sprintf("$(%s) += %s", FILENAME, $2)
     }
 }
 

Not all Fortran compilers will search in the same directory for include files, assuming relative includes from the current file is therefore not portable. If you want to have make search your source tree for include files vpath is the way to go

vpath % .:src

Best translate the include flags used in your project using patsubst to the vpath to be sure you have included all possible locations. Something like this might work (untested)

vpath % $(patsubst -I%,%,$(filter -I%,$(INCLUDE_FLAGS)))

[p-costa]

Brilliant, thank you very much! I didn't know about vpath, and this seems to work for me. Do you want me to update the PR accordingly?

[arjenmarkus]

As far as I know vpath is a feature supported by GNU make, but not necessarily all flavours of make. Just be aware of it :). Op ma 8 aug. 2022 om 01:19 schreef Pedro Costa ***@***.***>:

…

Brilliant, thank you very much! I didn't know about vpath, and this seems to work for me. Do you want me to update the PR accordingly? — Reply to this email directly, view it on GitHub <#416 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAN6YR4KP2RRLNRXIW4UTA3VYBAAZANCNFSM55YDII2A> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[awvwgk]

As far as I know vpath is a feature supported by GNU make, but not necessarily all flavours of make. Just be aware of it :).

This is indeed a common issue with make. I can recommend to use fpm instead if you care for portability ;).

Do you want me to update the PR accordingly?

Since we are currently migrating the webpage, having the patch on the new webpage would be much preferred (see #415).