add example programs

Author: perazz

doc/specs/stdlib_system.md

@@ -376,19 +376,7 @@ Returns one of the `integer` `OS_*` parameters representing the OS type, from th
 ### Example
 
 ```fortran
-program example_os_detection
-    use stdlib_system, only: OS_TYPE, get_runtime_os
-    implicit none
-    integer :: os_type_cached, os_type_runtime
-
-    ! Cached OS detection
-    os_type_cached = OS_TYPE()
-    print *, "Cached OS Type: ", os_type_cached
-
-    ! Runtime OS detection (full inspection)
-    os_type_runtime = get_runtime_os()
-    print *, "Runtime OS Type: ", os_type_runtime
-end program example_os_detection
+{!example/system/example_get_runtime_os.f90!}
 ```
 
 ---
@@ -427,17 +415,5 @@ Returns one of the `integer` `OS_*` parameters representing the OS type, from th
 ### Example
 
 ```fortran
-program example_os_detection
-    use stdlib_system, only: OS_TYPE, get_runtime_os
-    implicit none
-    integer :: os_type_cached, os_type_runtime
-
-    ! Cached OS detection
-    os_type_cached = OS_TYPE()
-    print *, "Cached OS Type: ", os_type_cached
-
-    ! Runtime OS detection (full inspection)
-    os_type_runtime = get_runtime_os()
-    print *, "Runtime OS Type: ", os_type_runtime
-end program example_os_detection
+{!example/system/example_os_type.f90!}
 ```

example/system/CMakeLists.txt

@@ -1,3 +1,5 @@
+ADD_EXAMPLE(get_runtime_os)
+ADD_EXAMPLE(os_type)
 ADD_EXAMPLE(process_1)
 ADD_EXAMPLE(process_2)
 ADD_EXAMPLE(process_3)

example/system/example_get_runtime_os.f90

@@ -0,0 +1,9 @@
+! Demonstrate usage of (non-cached) runtime OS query
+program example_get_runtime_os
+    use stdlib_system, only: OS_NAME, get_runtime_os
+    implicit none
+
+    ! Runtime OS detection (full inspection)
+    print *, "Runtime OS Type: ", OS_NAME(get_runtime_os())
+
+end program example_get_runtime_os

example/system/example_os_type.f90

@@ -0,0 +1,12 @@
+! Demonstrate OS detection
+program example_os_type
+    use stdlib_system, only: OS_TYPE, OS_NAME
+    implicit none
+
+    integer :: current_os
+
+    ! Cached OS detection
+    current_os = OS_TYPE() 
+    print *, "Current OS Type: ", OS_NAME(current_os) 
+
+end program example_os_type