NAG Library Manual, Mark 28.5
```    Program g01safe
!     G01SAF Example Program Text

!     Mark 28.5 Release. NAG Copyright 2022.

!     .. Use Statements ..
Use nag_library, Only: g01saf, nag_wp
!     .. Implicit None Statement ..
Implicit None
!     .. Parameters ..
Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
Integer                          :: i, ifail, lout, ltail, lx, lxmu,     &
lxstd
!     .. Local Arrays ..
Real (Kind=nag_wp), Allocatable  :: p(:), x(:), xmu(:), xstd(:)
Integer, Allocatable             :: ivalid(:)
Character (1), Allocatable       :: tail(:)
!     .. Intrinsic Procedures ..
Intrinsic                        :: max, mod, repeat
!     .. Executable Statements ..
Write (nout,*) 'G01SAF Example Program Results'
Write (nout,*)

!     Skip heading in data file

!     Read in the input vectors
Allocate (tail(ltail))

Allocate (x(lx))

Allocate (xmu(lxmu))

Allocate (xstd(lxstd))

!     Allocate memory for output
lout = max(ltail,lx,lxmu,lxstd)
Allocate (p(lout),ivalid(lout))

!     Calculate probability
ifail = -1
Call g01saf(ltail,tail,lx,x,lxmu,xmu,lxstd,xstd,p,ivalid,ifail)

If (ifail==0 .Or. ifail==1) Then
!       Display title
Write (nout,*)                                                         &
'   TAIL      X        XMU      XSTD       P     IVALID'
Write (nout,*) repeat('-',56)

!       Display results
Do i = 1, lout
Write (nout,99999) tail(mod(i-1,ltail)+1), x(mod(i-1,lx)+1),         &
xmu(mod(i-1,lxmu)+1), xstd(mod(i-1,lxstd)+1), p(i), ivalid(i)
End Do
End If

99999 Format (5X,A1,3(4X,F6.2),4X,F6.3,4X,I3)
End Program g01safe
```