create import library and definition file

Author: perazz

src/fpm_compiler.F90

@@ -47,7 +47,7 @@ module fpm_compiler
 use tomlf, only: toml_table
 use fpm_toml, only: serializable_t, set_string, set_value, toml_stat, get_value
 use fpm_compile_commands, only: compile_command_t, compile_command_table_t
-use shlex_module, only: sh_split => split, ms_split
+use shlex_module, only: sh_split => split, ms_split, quote => ms_quote
 implicit none
 public :: compiler_t, new_compiler, archiver_t, new_archiver, get_macros
 public :: append_clean_flags, append_clean_flags_array
@@ -103,6 +103,8 @@ module fpm_compiler
     procedure :: get_feature_flag
     !> Get flags for the main linking command
     procedure :: get_main_flags
+    !> Get library export flags
+    procedure :: get_export_flags    
     !> Compile a Fortran object
     procedure :: compile_fortran
     !> Compile a C object
@@ -122,6 +124,7 @@ module fpm_compiler
     !> Enumerate libraries, based on compiler and platform
     procedure :: enumerate_libraries
 
+
     !> Serialization interface
     procedure :: serializable_is_same => compiler_is_same
     procedure :: dump_to_toml => compiler_dump
@@ -1070,6 +1073,50 @@ function enumerate_libraries(self, prefix, libs) result(r)
 
 end function enumerate_libraries
 
+!>
+!> Generate library export flags for a shared library build
+!>
+function get_export_flags(self, target_dir, target_name) result(export_flags)
+    !> Instance of the compiler
+    class(compiler_t), intent(in) :: self
+    !> Path and package name
+    character(len=*), intent(in) :: target_dir, target_name
+    character(len=:), allocatable :: export_flags
+
+    character(len=:), allocatable :: implib_path, def_path
+
+    ! Only apply on Windows
+    if (get_os_type() /= OS_WINDOWS) then
+        export_flags = ""
+        return
+    end if
+
+    select case (self%id)
+
+    case (id_gcc, id_caf, id_f95)
+        ! GNU-based: emit both import library and def file
+        implib_path = quote(join_path(target_dir, target_name // ".dll.a") , for_cmd=.true.)
+        def_path    = quote(join_path(target_dir, target_name // ".def" ) , for_cmd=.true.)
+
+        export_flags = " -Wl,--out-implib," // implib_path // &
+                       " -Wl,--output-def," // def_path
+
+    case (id_intel_classic_windows, id_intel_llvm_windows)
+        ! Intel/MSVC-style
+        implib_path = quote(join_path(target_dir, target_name // ".lib") , for_cmd=.true.)
+        def_path    = quote(join_path(target_dir, target_name // ".def") , for_cmd=.true.)
+                
+        export_flags = " /IMPLIB:" // implib_path // &
+                       " /DEF:" // def_path
+
+    case default
+        
+        export_flags = ""  ! Do nothing elsewhere
+
+    end select
+
+end function get_export_flags
+
 !> Create new compiler instance
 subroutine new_compiler(self, fc, cc, cxx, echo, verbose)
     !> New instance of the compiler

src/fpm_targets.f90

@@ -1055,7 +1055,7 @@ subroutine resolve_target_linking(targets, model, library, error)
                                                                         exclude_self=.true., &
                                                                         dep_IDs=package_deps, &
                                                                         error=error)
-                    
+                                                                        
                     if (allocated(error)) return
 
                     ! Now that they're available, add these dependencies to the targets
@@ -1073,6 +1073,10 @@ subroutine resolve_target_linking(targets, model, library, error)
                         end if
                     end if
 
+                    ! Add shared library exports (import library + .def)
+                    target%link_flags = target%link_flags // " " // &
+                                        model%compiler%get_export_flags(target%output_dir,target%package_name)
+                    
                     ! Add global link flags (e.g., system-wide libraries)
                     target%link_flags = target%link_flags // " " // global_link_flags