add examples

Author: perazz

example/CMakeLists.txt

@@ -30,4 +30,5 @@ add_subdirectory(stats_distribution_uniform)
 add_subdirectory(stringlist_type)
 add_subdirectory(strings)
 add_subdirectory(string_type)
+add_subdirectory(system)
 add_subdirectory(version)

example/system/CMakeLists.txt

@@ -0,0 +1,3 @@
+ADD_EXAMPLE(process_1)
+ADD_EXAMPLE(process_2)
+ADD_EXAMPLE(process_3)

example/system/example_process_1.f90

@@ -0,0 +1,20 @@
+! Process example 1: Run a Command Synchronously and Capture Output
+program run_sync
+    use stdlib_system, only: run, is_completed, process_type
+    implicit none
+
+    type(process_type) :: p
+    logical :: completed
+
+    ! Run a synchronous process to list directory contents
+    p = run("ls -l", wait=.true., want_stdout=.true.)
+
+    ! Check if the process is completed (should be true since wait=.true.)
+    if (is_completed(p)) then
+        print *, "Process completed successfully. The current directory: "
+        print *, p%stdout
+    else
+        print *, "Process is still running (unexpected)."
+    end if
+    
+end program run_sync

example/system/example_process_2.f90

@@ -0,0 +1,21 @@
+! Process example 2: Run an Asynchronous Command and check its status
+program run_async
+    use stdlib_system, only: process_type, run, is_running, wait
+    implicit none
+
+    type(process_type) :: p
+
+    ! Run an asynchronous process to sleep for 5 seconds
+    p = run("sleep 3", wait=.false.)
+
+    ! Check if the process is running
+    if (is_running(p)) then
+        print *, "Process is running."
+    else
+        print *, "Process has already completed."
+    end if
+
+    ! Wait for the process to complete
+    call wait(p)
+    print *, "Process has now completed."
+end program run_async

example/system/example_process_3.f90

@@ -0,0 +1,22 @@
+! Process example 3: Run with many arguments, and check runtime
+program run_with_args
+    use stdlib_system, only: process_type, run, elapsed, wait
+    implicit none
+
+    type(process_type) :: p
+    character(len=15), allocatable :: args(:)
+
+    ! Define arguments for the `echo` command
+    allocate(args(2))
+    args(1) = "echo"
+    args(2) = "Hello, Fortran!"
+
+    ! Run the command with arguments
+    p = run(args, wait=.true.)
+
+    ! Print the runtime of the process
+    print *, "Process runtime:", elapsed(p), "seconds."
+
+    ! Clean up
+    deallocate(args)
+end program run_with_args