use more correct data type to C

Author: scivision

src/stdlib_experimental_system.F90

@@ -1,19 +1,23 @@
 module stdlib_experimental_system
-use, intrinsic :: iso_c_binding, only : c_int
+use, intrinsic :: iso_c_binding, only : c_int, c_long
 implicit none
 private
 
 interface
 #ifdef _WIN32
-subroutine system_sleep(ms) bind (C, name='Sleep')
-import c_int
-integer(c_int), value, intent(in) :: ms
+subroutine system_sleep(dwMilliseconds) bind (C, name='Sleep')
+!! void Sleep(DWORD dwMilliseconds)
+!! https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-sleep
+import c_long
+integer(c_long), value, intent(in) :: dwMilliseconds
 end subroutine system_sleep
 #else
-subroutine system_sleep(us) bind (C, name='usleep')
+integer(c_int) function system_sleep(usec) bind (C, name='usleep')
+!! int usleep(useconds_t usec);
+!! https://linux.die.net/man/3/usleep
 import c_int
-integer(c_int), value, intent(in) :: us
-end subroutine system_sleep
+integer(c_int), value, intent(in) :: usec
+end function system_sleep
 #endif
 end interface
 
@@ -23,15 +27,18 @@ end subroutine system_sleep
 
 subroutine sleep(millisec)
 integer, intent(in) :: millisec
-integer(c_int) :: t
+integer(c_int) :: ierr
 
 #ifdef _WIN32
-t = millisec
+!! PGI Windows, Ifort Windows, ....
+call system_sleep(int(millisec, c_long))
 #else
-t = millisec * 1000
+!! Linux, Unix, MacOS, MSYS2, ...
+ierr = system_sleep(int(millisec * 1000, c_int))
+if (ierr/=0) error stop 'problem with usleep() system call'
 #endif
 
-call system_sleep(int(t, c_int))
+
 end subroutine sleep
 
 end module stdlib_experimental_system