functionality to check whether STDERR/STDOUT are redirected

src/C_routines.c

@@ -85,6 +85,16 @@ void inflate_c(const uLong *s_deflated, const uLong *s_inflated, const Byte defl
   }
 }
 
+
+int stdout_isatty_c(){
+  return isatty(STDOUT_FILENO);
+}
+
+int stderr_isatty_c(){
+  return isatty(STDERR_FILENO);
+}
+
+
 #ifdef FYAML
 void to_flow_c(char **flow, long* length_flow, const char *mixed){
   struct fy_document *fyd = NULL;

src/system_routines.f90

@@ -4,9 +4,9 @@
 !--------------------------------------------------------------------------------------------------
 module system_routines
   use, intrinsic :: ISO_C_Binding
+  use, intrinsic :: ISO_fortran_env
 
   use prec
-  use IO
 
   implicit none(type,external)
   private
@@ -21,6 +21,8 @@ module system_routines
     signalint_C, &
     signalusr1_C, &
     signalusr2_C, &
+    STDOUT_isatty, &
+    STDERR_isatty, &
     f_c_string, &
     free_C
 
@@ -91,6 +93,20 @@ module system_routines
       type(C_PTR), value :: ptr
     end subroutine free_C
 
+    function stdout_isatty_C() bind(C)
+      use, intrinsic :: ISO_C_Binding, only: C_INT
+      implicit none(type,external)
+
+      integer(C_INT) :: stdout_isatty_C
+    end function stdout_isatty_C
+
+    function stderr_isatty_C() bind(C)
+      use, intrinsic :: ISO_C_Binding, only: C_INT
+      implicit none(type,external)
+
+      integer(C_INT) :: stderr_isatty_C
+    end function stderr_isatty_C
+
   end interface
 
 contains
@@ -101,7 +117,7 @@ contains
 !--------------------------------------------------------------------------------------------------
 subroutine system_routines_init()
 
-  print'(/,1x,a)', '<<<+-  system_routines init  -+>>>'; flush(IO_STDOUT)
+  print'(/,1x,a)', '<<<+-  system_routines init  -+>>>'; flush(OUTPUT_UNIT)
 
   call system_routines_selfTest()
 
@@ -229,6 +245,26 @@ pure function f_c_string(f_string) result(c_string)
 end function f_c_string
 
 
+!--------------------------------------------------------------------------------------------------
+!> @brief
+!--------------------------------------------------------------------------------------------------
+logical function STDOUT_isatty()
+
+  STDOUT_isatty = merge(.true.,.false.,stdout_isatty_C()==1)
+
+end function STDOUT_isatty
+
+
+!--------------------------------------------------------------------------------------------------
+!> @brief
+!--------------------------------------------------------------------------------------------------
+logical function STDERR_isatty()
+
+  STDERR_isatty = merge(.true.,.false.,stderr_isatty_C()==1)
+
+end function STDERR_isatty
+
+
 !--------------------------------------------------------------------------------------------------
 !> @brief Check correctness of some system_routine functions.
 !--------------------------------------------------------------------------------------------------