added error handling to two HL procedures.

examples/example_hl.f90

@@ -66,7 +66,7 @@ PROGRAM example
   !              CALL timedeltaToString(td, dstring2)
   !              WRITE (0,*) "compute ", dstring1, " + ", dstring2
 
-  WRITE (0,*) "compute ", dt%to_string(), " + ", td%to_string()
+  WRITE (0,*) "compute ", dt%to_string(), " + ", td%to_string() 
 
   ! Adding time intervals is unchanged:
 

src/error_handling.f90

@@ -20,6 +20,8 @@ MODULE error_handling
   PUBLIC :: create_error
   PUBLIC :: transfer_error
 
+  PUBLIC :: MAX_ERROR_STR_LEN
+
 
   INTEGER, PARAMETER :: MAX_ERROR_STR_LEN = 256
 

src/libmtime_hl.f90

@@ -11,6 +11,7 @@
 module mtime_hl
 
   use mtime
+  USE error_handling
 
   implicit none
   
@@ -76,16 +77,32 @@ module mtime_hl
 
   end type t_timedelta
 
+
+  !> Error info type: mtime error
+  TYPE, EXTENDS(t_error_info) :: t_mtime_error
+  END TYPE t_mtime_error
+
 contains 
 
   ! Convert t_datetime object to string.
   !
-  function t_datetime_to_string(this)
-    character(len=max_datetime_str_len) :: t_datetime_to_string
-    class (t_datetime) :: this
-    type(datetime), pointer :: dt_tmp
+  FUNCTION t_datetime_to_string(this, opt_error)
+    character(len=max_datetime_str_len)  :: t_datetime_to_string
+    TYPE(t_error), INTENT(OUT), OPTIONAL :: opt_error
+    class (t_datetime)                   :: this
+    type(datetime), pointer              :: dt_tmp
+    INTEGER                              :: errno
+    CHARACTER(len=MAX_ERROR_STR_LEN)     :: error_str
     dt_tmp => newDatetime(this%dt)
-    call datetimeToString(dt_tmp, t_datetime_to_string)    
+    IF (PRESENT(opt_error)) THEN
+      CALL datetimeToString(dt_tmp, t_datetime_to_string, errno)    
+      IF  (errno /= 0) THEN
+        CALL mtime_strerror(errno, error_str)
+        CALL create_error(opt_error, t_mtime_error(error_str))      
+      END IF
+    ELSE
+      CALL datetimeToString(dt_tmp, t_datetime_to_string)    
+    END IF
     call deallocateDatetime(dt_tmp)
   end function t_datetime_to_string
 
@@ -165,21 +182,32 @@ contains
   
   ! Convert t_timedelta object to string.
   !
-  function t_timedelta_to_string(this)
+  FUNCTION t_timedelta_to_string(this, opt_error)
     character(len=max_timedelta_str_len) :: t_timedelta_to_string
-    class (t_timedelta) :: this
-    type(timedelta), pointer :: td_tmp
+    class (t_timedelta)                  :: this
+    TYPE(t_error), INTENT(OUT), OPTIONAL :: opt_error
+    type(timedelta), pointer             :: td_tmp
+    INTEGER                              :: errno
+    CHARACTER(len=MAX_ERROR_STR_LEN)     :: error_str
     td_tmp => newTimedelta(this%td)
-    call timedeltaToString(td_tmp, t_timedelta_to_string)    
-    call deallocateTimedelta(td_tmp)
-  end function t_timedelta_to_string
+    IF (PRESENT(opt_error)) THEN
+      CALL timedeltaToString(td_tmp, t_timedelta_to_string, errno)    
+      IF  (errno /= 0) THEN
+        CALL mtime_strerror(errno, error_str)
+        CALL create_error(opt_error, t_mtime_error(error_str))      
+      END IF
+    ELSE
+      CALL timedeltaToString(td_tmp, t_timedelta_to_string)    
+    END IF
+    CALL deallocateTimedelta(td_tmp)
+  END FUNCTION t_timedelta_to_string
 
   ! Assignment operator: this = "time interval string".
   !
-  subroutine t_timedelta_assign_string(this, td_string)
-    class (t_timedelta), intent(out) :: this
-    character(len=*),    intent(in)  :: td_string
-    type(timedelta), pointer :: td_tmp
+  SUBROUTINE t_timedelta_assign_string(this, td_string)
+    CLASS (t_timedelta), INTENT(out) :: this
+    CHARACTER(len=*),    INTENT(in)  :: td_string
+    TYPE(timedelta), POINTER :: td_tmp
     td_tmp => newTimedelta(td_string)
     this%td = td_tmp
     this%td%sign = td_tmp%sign