add system module

There are a number of capabilities it would be useful to bring from
cstdlib and STL. This is an initial demonstration, replacing
the non-cross-compiler sleep() with a standard implmeentation that
works across compilers and operating systems, with millisecond integer
input.

Author: scivision

.github/workflows/ci_windows.yml

@@ -0,0 +1,31 @@
+name: CI_windows
+
+on: [push, pull_request]
+
+env:
+  CI: "ON"
+
+jobs:
+  Build:
+    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+
+    steps:
+    - uses: actions/checkout@v1
+
+    - run: cmake -G "MinGW Makefiles" -DCMAKE_SH="CMAKE_SH-NOTFOUND" -Wdev -B build
+      env:
+        FC: gfortran
+        CC: gcc
+        CXX: g++
+
+    - name: CMake build
+      run: cmake --build build --parallel
+
+    - run: cmake --build build --verbose --parallel 1
+      if: failure()
+
+    - name: CTest
+      run: ctest --parallel --output-on-failure
+      working-directory: build

README.md

@@ -1,8 +1,11 @@
 # Fortran Standard Library
 
+[![Actions Status](https://github.com/fortran-lang/stdlib/workflows/CI/badge.svg)](https://github.com/fortran-lang/stdlib/actions)
+[![Actions Status](https://github.com/fortran-lang/stdlib/workflows/CI_windows/badge.svg)](https://github.com/fortran-lang/stdlib/actions)
+
 ## Getting started
 
-```
+```sh
 git clone https://github.com/fortran-lang/stdlib
 cd stdlib
 make

src/CMakeLists.txt

@@ -2,6 +2,7 @@ set(SRC
     stdlib_experimental_ascii.f90
     stdlib_experimental_io.f90
     stdlib_experimental_error.f90
+    stdlib_experimental_system.F90
 )
 
 add_library(fortran_stdlib ${SRC})

src/stdlib_experimental_system.F90

@@ -0,0 +1,37 @@
+module stdlib_experimental_system
+use, intrinsic :: iso_c_binding, only : c_int
+implicit none
+private
+
+interface
+#ifdef _WIN32
+subroutine system_sleep(ms) bind (C, name='Sleep')
+import c_int
+integer(c_int), value, intent(in) :: ms
+end subroutine system_sleep
+#else
+subroutine system_sleep(us) bind (C, name='usleep')
+import c_int
+integer(c_int), value, intent(in) :: us
+end subroutine system_sleep
+#endif
+end interface
+
+public :: sleep_millisec
+
+contains
+
+subroutine sleep_millisec(t)
+integer, intent(in) :: t
+integer(c_int) :: tsys
+
+tsys = int(t, c_int)
+
+#ifndef _WIN32
+tsys = int(t, c_int) * 1000
+#endif
+
+call system_sleep(tsys)
+end subroutine sleep_millisec
+
+end module stdlib_experimental_system

src/tests/CMakeLists.txt

@@ -1,3 +1,3 @@
 add_subdirectory(ascii)
 add_subdirectory(loadtxt)
-
+add_subdirectory(system)

src/tests/system/CMakeLists.txt

@@ -0,0 +1,5 @@
+add_executable(test_sleep test_sleep.f90)
+target_link_libraries(test_sleep fortran_stdlib)
+
+add_test(NAME Sleep COMMAND $<TARGET_FILE:test_sleep> 1234)
+set_tests_properties(Sleep PROPERTIES TIMEOUT 5)

src/tests/system/test_sleep.f90

@@ -0,0 +1,16 @@
+program sleepy
+
+use stdlib_experimental_system, only : sleep_millisec
+
+integer :: ierr, millisec
+character(8) :: argv
+
+millisec = 789
+call get_command_argument(1, argv, status=ierr)
+if (ierr==0) read(argv,*) millisec
+
+if (millisec<0) millisec=0
+
+call sleep_millisec(millisec)
+
+end program