From c615d57885a36db017dec4ba98bfdb2e92a9813c Mon Sep 17 00:00:00 2001
From: Sebastian Ehlert <28669218+awvwgk@users.noreply.github.com>
Date: Sun, 8 Nov 2020 13:02:21 +0100
Subject: Implement linking against external libraries

---
 fpm/src/fpm.f90                       | 17 ++++++++++++++---
 fpm/src/fpm/manifest/build_config.f90 | 18 ++++++++++--------
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/fpm/src/fpm.f90 b/fpm/src/fpm.f90
index af19c65..daa4d98 100644
--- a/fpm/src/fpm.f90
+++ b/fpm/src/fpm.f90
@@ -27,11 +27,12 @@ public :: cmd_build, cmd_install, cmd_run
 contains
 
 
-recursive subroutine add_libsources_from_package(sources,package_list,package, &
+recursive subroutine add_libsources_from_package(sources,link_libraries,package_list,package, &
                                                   package_root,dev_depends,error)
     ! Discover library sources in a package, recursively including dependencies
     !
     type(srcfile_t), allocatable, intent(inout), target :: sources(:)
+    type(string_t), allocatable, intent(inout) :: link_libraries(:)
     type(string_t), allocatable, intent(inout) :: package_list(:)
     type(package_t), intent(in) :: package
     character(*), intent(in) :: package_root
@@ -121,7 +122,7 @@ recursive subroutine add_libsources_from_package(sources,package_list,package, &
             end if
 
             
-            call add_libsources_from_package(sources,package_list,dependency, &
+            call add_libsources_from_package(sources,link_libraries,package_list,dependency, &
                 package_root=dependency_path, &
                 dev_depends=.false., error=error)
             
@@ -134,6 +135,9 @@ recursive subroutine add_libsources_from_package(sources,package_list,package, &
 
             dep_name%s = dependency_list(i)%name
             package_list = [package_list, dep_name]
+            if (allocated(dependency%build_config%link)) then
+                link_libraries = [link_libraries, dependency%build_config%link]
+            end if
 
         end do
 
@@ -150,11 +154,14 @@ subroutine build_model(model, settings, package, error)
     type(package_t), intent(in) :: package
     type(error_t), allocatable, intent(out) :: error
 
+    integer :: i
     type(string_t), allocatable :: package_list(:)
 
     model%package_name = package%name
     if (allocated(package%build_config%link)) then
         model%link_libraries = package%build_config%link
+    else
+        allocate(model%link_libraries(0))
     end if
 
     allocate(package_list(1))
@@ -222,7 +229,7 @@ subroutine build_model(model, settings, package, error)
     endif
 
     ! Add library sources, including local dependencies
-    call add_libsources_from_package(model%sources,package_list,package, &
+    call add_libsources_from_package(model%sources,model%link_libraries,package_list,package, &
                                       package_root='.',dev_depends=.true.,error=error)
     if (allocated(error)) then
         return
@@ -230,6 +237,10 @@ subroutine build_model(model, settings, package, error)
 
     call targets_from_sources(model,model%sources)
 
+    do i = 1, size(model%link_libraries)
+        model%link_flags = model%link_flags // " -l" // model%link_libraries(i)%s
+    end do
+
     call resolve_module_dependencies(model%targets,error)
 
 end subroutine build_model
diff --git a/fpm/src/fpm/manifest/build_config.f90 b/fpm/src/fpm/manifest/build_config.f90
index cd59ce5..a88fd58 100644
--- a/fpm/src/fpm/manifest/build_config.f90
+++ b/fpm/src/fpm/manifest/build_config.f90
@@ -94,7 +94,7 @@ contains
                 call fatal_error(error, "Entry in link field cannot be read")
                 return
             end if
-            if (allocated(self%link)) then
+            if (allocated(link)) then
                 allocate(self%link(1))
                 call move_alloc(link, self%link(1)%s)
             end if
@@ -148,7 +148,7 @@ contains
         !> Verbosity of the printout
         integer, intent(in), optional :: verbosity
 
-        integer :: pr
+        integer :: pr, ilink
         character(len=*), parameter :: fmt = '("#", 1x, a, t30, a)'
 
         if (present(verbosity)) then
@@ -160,12 +160,14 @@ contains
         if (pr < 1) return
 
         write(unit, fmt) "Build configuration"
-        ! if (allocated(self%auto_executables)) then
-            write(unit, fmt) " - auto-discovery (apps) ", merge("enabled ", "disabled", self%auto_executables)
-        ! end if
-        ! if (allocated(self%auto_tests)) then
-            write(unit, fmt) " - auto-discovery (tests) ", merge("enabled ", "disabled", self%auto_tests)
-        ! end if
+        write(unit, fmt) " - auto-discovery (apps) ", merge("enabled ", "disabled", self%auto_executables)
+        write(unit, fmt) " - auto-discovery (tests) ", merge("enabled ", "disabled", self%auto_tests)
+        if (allocated(self%link)) then
+            write(unit, fmt) " - link against"
+            do ilink = 1, size(self%link)
+                write(unit, fmt) "   - " // self%link(ilink)%s
+            end do
+        end if
 
     end subroutine info
 
-- 
cgit v1.2.3