SUBROUTINE GDSWZD_C(IGDTNUM,IGDTMPL,IGDTLEN,IOPT,NPTS,FILL, &
                     XPTS,YPTS,RLON,RLAT,NRET,CROT,SROT, &
                     XLON,XLAT,YLON,YLAT,AREA) BIND(C, NAME='gdswzd')
!$$$  SUBPROGRAM DOCUMENTATION BLOCK
!
! $Revision: 74917 $
!
! SUBPROGRAM:  GDSWZD_C     'C' WRAPPER FOR ROUTINE GDSWZD
!   PRGMMR: JOVIC         ORG: W/NMC23       DATE: 2016-04-10
!
! ABSTRACT:  USE THIS ROUTINE TO CALL 'GDSWZD' FROM A 'C' OR 'C++' PROGRAM.
!            TAKES ADVANTAGE OF THE FORTRAN/C INTEROPERABILITY STANDARD.
!
! PROGRAM HISTORY LOG:
! 2016-04-10  JOVIC   INITIAL VERSION. 
! 2016-04-26  GAYNO   UPDATE FOR GRIB 2
!
! USAGE:    
!
!  EXAMPLE: MIXED PRECSION IPLIB CALL
!
!  include "iplib.h"
!
!  int *igdtmpl;
!  int igdtnum, igdtlen, iopt, npts, nret;
!  double fill;
!  double *xpts, *ypts, *rlon, *rlat;
!  double *crot, *srot, *xlon, *xlat, *ylon, *ylat, *area;
!
!  gdswzd(igdtnum, igdtmpl, igdtlen, iopt, npts,
!         fill, xpts, ypts, rlon, rlat,
!         &nret, crot, srot, xlon,
!         xlat, ylon, ylat, area);
!
!  INPUT ARGUMENT LIST:
!     IGDTNUM  - INTEGER GRID DEFINITION TEMPLATE NUMBER.
!                CORRESPONDS TO THE GFLD%IGDTNUM COMPONENT OF THE
!                NCEP G2 LIBRARY GRIDMOD DATA STRUCTURE.
!                  00 - EQUIDISTANT CYLINDRICAL
!                  01 - ROTATED EQUIDISTANT CYLINDRICAL.  "E"
!                       AND NON-"E" STAGGERED
!                  10 - MERCATOR CYCLINDRICAL
!                  20 - POLAR STEREOGRAPHIC AZIMUTHAL
!                  30 - LAMBERT CONFORMAL CONICAL
!                  40 - GAUSSIAN EQUIDISTANT CYCLINDRICAL
!     IGDTMPL  - INTEGER (IGDTLEN) GRID DEFINITION TEMPLATE ARRAY.
!                CORRESPONDS TO THE GFLD%IGDTMPL COMPONENT OF THE
!                NCEP G2 LIBRARY GRIDMOD DATA STRUCTURE FOR
!                SECTION THREE.
!                ALL PROJECTIONS:
!                 (1):  SHAPE OF EARTH, OCTET 15
!                 (2):  SCALE FACTOR OF SPHERICAL EARTH RADIUS,
!                       OCTET 16
!                 (3):  SCALED VALUE OF RADIUS OF SPHERICAL EARTH,
!                       OCTETS 17-20
!                 (4):  SCALE FACTOR OF MAJOR AXIS OF ELLIPTICAL EARTH,
!                       OCTET 21
!                 (5):  SCALED VALUE OF MAJOR AXIS OF ELLIPTICAL EARTH,
!                       OCTETS 22-25
!                 (6):  SCALE FACTOR OF MINOR AXIS OF ELLIPTICAL EARTH,
!                       OCTET 26
!                 (7):  SCALED VALUE OF MINOR AXIS OF ELLIPTICAL EARTH,
!                       OCTETS 27-30
!                EQUIDISTANT CYCLINDRICAL:
!                 (8):  NUMBER OF POINTS ALONG A PARALLEL, OCTS 31-34
!                 (9):  NUMBER OF POINTS ALONG A MERIDIAN, OCTS 35-38
!                 (10): BASIC ANGLE OF INITIAL PRODUCTION DOMAIN,
!                       OCTETS 39-42.
!                 (11): SUBDIVISIONS OF BASIC ANGLE, OCTETS 43-46
!                 (12): LATITUDE OF FIRST GRID POINT, OCTETS 47-50
!                 (13): LONGITUDE OF FIRST GRID POINT, OCTETS 51-54
!                 (14): RESOLUTION AND COMPONENT FLAGS, OCTET 55
!                 (15): LATITUDE OF LAST GRID POINT, OCTETS 56-59
!                 (16): LONGITUDE OF LAST GRID POINT, OCTETS 60-63
!                 (17): I-DIRECTION INCREMENT, OCTETS 64-67
!                 (18): J-DIRECTION INCREMENT, OCTETS 68-71
!                 (19): SCANNING MODE, OCTET 72
!                MERCATOR CYCLINDRICAL:
!                 (8):  NUMBER OF POINTS ALONG A PARALLEL, OCTS 31-34
!                 (9):  NUMBER OF POINTS ALONG A MERIDIAN, OCTS 35-38
!                 (10): LATITUDE OF FIRST POINT, OCTETS 39-42
!                 (11): LONGITUDE OF FIRST POINT, OCTETS 43-46
!                 (12): RESOLUTION AND COMPONENT FLAGS, OCTET 47
!                 (13): TANGENT LATITUDE, OCTETS 48-51
!                 (14): LATITUDE OF LAST POINT, OCTETS 52-55
!                 (15): LONGITUDE OF LAST POINT, OCTETS 56-59
!                 (16): SCANNING MODE FLAGS, OCTET 60
!                 (17): ORIENTATION OF GRID, OCTETS 61-64
!                 (18): LONGITUDINAL GRID LENGTH, OCTETS 65-68
!                 (19): LATITUDINAL GRID LENGTH, OCTETS 69-72
!                LAMBERT CONFORMAL CONICAL:
!                 (8):  NUMBER OF POINTS ALONG X-AXIS, OCTS 31-34
!                 (9):  NUMBER OF POINTS ALONG Y-AXIS, OCTS 35-38
!                 (10): LATITUDE OF FIRST POINT, OCTETS 39-42
!                 (11): LONGITUDE OF FIRST POINT, OCTETS 43-46
!                 (12): RESOLUTION OF COMPONENT FLAG, OCTET 47
!                 (13): LATITUDE WHERE GRID LENGTHS SPECIFIED,
!                       OCTETS 48-51
!                 (14): LONGITUDE OF MERIDIAN THAT IS PARALLEL TO
!                       Y-AXIS, OCTETS 52-55
!                 (15): X-DIRECTION GRID LENGTH, OCTETS 56-59
!                 (16): Y-DIRECTION GRID LENGTH, OCTETS 60-63
!                 (17): PROJECTION CENTER FLAG, OCTET 64
!                 (18): SCANNING MODE, OCTET 65
!                 (19): FIRST TANGENT LATITUDE FROM POLE, OCTETS 66-69
!                 (20): SECOND TANGENT LATITUDE FROM POLE, OCTETS 70-73
!                 (21): LATITUDE OF SOUTH POLE OF PROJECTION,
!                       OCTETS 74-77
!                 (22): LONGITUDE OF SOUTH POLE OF PROJECTION,
!                       OCTETS 78-81
!                GAUSSIAN CYLINDRICAL:
!                 (8):  NUMBER OF POINTS ALONG A PARALLEL, OCTS 31-34
!                 (9):  NUMBER OF POINTS ALONG A MERIDIAN, OCTS 35-38
!                 (10): BASIC ANGLE OF INITIAL PRODUCTION DOMAIN,
!                       OCTETS 39-42
!                 (11): SUBDIVISIONS OF BASIC ANGLE, OCTETS 43-46
!                 (12): LATITUDE OF FIRST GRID POINT, OCTETS 47-50
!                 (13): LONGITUDE OF FIRST GRID POINT, OCTETS 51-54
!                 (14): RESOLUTION AND COMPONENT FLAGS, OCTET 55
!                 (15): LATITUDE OF LAST GRID POINT, OCTETS 56-59
!                 (16): LONGITUDE OF LAST GRID POINT, OCTETS 60-63
!                 (17): I-DIRECTION INCREMENT, OCTETS 64-67
!                 (18): NUMBER OF PARALLELS BETWEEN POLE AND EQUATOR,
!                       OCTETS 68-71
!                 (19): SCANNING MODE, OCTET 72
!                POLAR STEREOGRAPHIC AZIMUTHAL:
!                 (8):  NUMBER OF POINTS ALONG X-AXIS, OCTETS 31-34
!                 (9):  NUMBER OF POINTS ALONG Y-AXIS, OCTETS 35-38
!                 (10): LATITUDE OF FIRST GRID POINT, OCTETS 39-42
!                 (11): LONGITUDE OF FIRST GRID POINT, OCTETS 43-46
!                 (12): RESOLUTION AND COMPONENT FLAGS, OCTET 47
!                 (13): TRUE LATITUDE, OCTETS 48-51
!                 (14): ORIENTATION LONGITUDE, OCTETS 52-55
!                 (15): X-DIRECTION GRID LENGTH, OCTETS 56-59
!                 (16): Y-DIRECTION GRID LENGTH, OCTETS 60-63
!                 (17): PROJECTION CENTER FLAG, OCTET 64
!                 (18): SCANNING MODE FLAGS, OCTET 65
!                ROTATED EQUIDISTANT CYCLINDRICAL:
!                 (8):  NUMBER OF POINTS ALONG A PARALLEL, OCTS 31-34
!                 (9):  NUMBER OF POINTS ALONG A MERIDIAN, OCTS 35-38
!                 (10): BASIC ANGLE OF INITIAL PRODUCTION DOMAIN,
!                       OCTETS 39-42
!                 (11): SUBDIVISIONS OF BASIC ANGLE, OCTETS 43-46
!                 (12): LATITUDE OF FIRST GRID POINT, OCTETS 47-50
!                 (13): LONGITUDE OF FIRST GRID POINT, OCTETS 51-54
!                 (14): RESOLUTION AND COMPONENT FLAGS, OCTET 55
!                 (15): LATITUDE OF LAST GRID POINT, OCTETS 56-59
!                 (16): LONGITUDE OF LAST GRID POINT, OCTETS 60-63
!                 (17): I-DIRECTION INCREMENT, OCTETS 64-67
!                 (18): J-DIRECTION INCREMENT, OCTETS 68-71
!                 (19): SCANNING MODE, OCTET 72
!                 (20): LATITUDE OF SOUTHERN POLE OF PROJECTION,
!                       OCTETS 73-76
!                 (21): LONGITUDE OF SOUTHERN POLE OF PROJECTION,
!                       OCTETS 77-80
!                 (22): ANGLE OF ROTATION OF PROJECTION, OCTS 81-84
!     IGDTLEN  - INTEGER NUMBER OF ELEMENTS OF THE GRID DEFINITION
!                TEMPLATE ARRAY.  CORRESPONDS TO THE GFLD%IGDTLEN
!                COMPONENT OF THE NCEP G2 LIBRARY GRIDMOD DATA STRUCTURE.
!     IOPT     - INTEGER OPTION FLAG
!                ( 0 TO COMPUTE EARTH COORDS OF ALL THE GRID POINTS)
!                (+1 TO COMPUTE EARTH COORDS OF SELECTED GRID COORDS)
!                (-1 TO COMPUTE GRID COORDS OF SELECTED EARTH COORDS)
!     NPTS     - INTEGER MAXIMUM NUMBER OF COORDINATES
!     FILL     - REAL FILL VALUE TO SET INVALID OUTPUT DATA
!                (MUST BE IMPOSSIBLE VALUE; SUGGESTED VALUE: -9999.)
!     XPTS     - REAL (NPTS) GRID X POINT COORDINATES IF IOPT>0
!     YPTS     - REAL (NPTS) GRID Y POINT COORDINATES IF IOPT>0
!     RLON     - REAL (NPTS) EARTH LONGITUDES IN DEGREES E IF IOPT<0
!                (ACCEPTABLE RANGE: -360. TO 360.)
!     RLAT     - REAL (NPTS) EARTH LATITUDES IN DEGREES N IF IOPT<0
!                (ACCEPTABLE RANGE: -90. TO 90.)
!
!  OUTPUT ARGUMENT LIST:
!     XPTS     - REAL (NPTS) GRID X POINT COORDINATES IF IOPT<=0
!     YPTS     - REAL (NPTS) GRID Y POINT COORDINATES IF IOPT<=0
!     RLON     - REAL (NPTS) EARTH LONGITUDES IN DEGREES E IF IOPT>=0
!     RLAT     - REAL (NPTS) EARTH LATITUDES IN DEGREES N IF IOPT>=0
!     NRET     - INTEGER NUMBER OF VALID POINTS COMPUTED
!                (-1 IF PROJECTION UNRECOGNIZED)
!     CROT     - REAL (NPTS) CLOCKWISE VECTOR ROTATION COSINES
!     SROT     - REAL (NPTS) CLOCKWISE VECTOR ROTATION SINES
!                (UGRID=CROT*UEARTH-SROT*VEARTH;
!                 VGRID=SROT*UEARTH+CROT*VEARTH)
!     XLON     - REAL (NPTS) DX/DLON IN 1/DEGREES
!     XLAT     - REAL (NPTS) DX/DLAT IN 1/DEGREES
!     YLON     - REAL (NPTS) DY/DLON IN 1/DEGREES
!     YLAT     - REAL (NPTS) DY/DLAT IN 1/DEGREES
!     AREA     - REAL (NPTS) AREA WEIGHTS IN M**2
!                (PROPORTIONAL TO THE SQUARE OF THE MAP FACTOR
!                 IN THE CASE OF CONFORMAL PROJECTIONS)
!
! SUBPROGRAMS CALLED:
!   GDSWZD     GDS WIZARD
!
! ATTRIBUTES:
!   LANGUAGE: FORTRAN 90
!
!$$$
!
 USE, INTRINSIC :: ISO_C_BINDING

 USE GDSWZD_MOD

 IMPLICIT NONE
 
!#if (LSIZE==8)
! INTEGER(KIND=C_LONG), INTENT(IN)         :: IGDTMPL(IGDTLEN)
! INTEGER(KIND=C_LONG), VALUE, INTENT(IN)  :: IGDTNUM, IGDTLEN
! INTEGER(KIND=C_LONG), VALUE, INTENT(IN)  :: IOPT, NPTS
! INTEGER(KIND=C_LONG), INTENT(OUT)        :: NRET
!#else
 INTEGER(KIND=C_INT),  INTENT(IN)         :: IGDTMPL(IGDTLEN)
 INTEGER(KIND=C_INT),  VALUE, INTENT(IN)  :: IGDTNUM, IGDTLEN
 INTEGER(KIND=C_INT),  VALUE, INTENT(IN)  :: IOPT, NPTS
 INTEGER(KIND=C_INT),  INTENT(OUT)        :: NRET
!#endif

!#if (LSIZE==8 || LSIZE==D)
REAL(KIND=C_DOUBLE), VALUE, INTENT(IN)   :: FILL
REAL(KIND=C_DOUBLE), INTENT(INOUT)       :: XPTS(NPTS),YPTS(NPTS),RLON(NPTS),RLAT(NPTS)
REAL(KIND=C_DOUBLE), INTENT(OUT)         :: CROT(NPTS),SROT(NPTS),XLON(NPTS),XLAT(NPTS)
REAL(KIND=C_DOUBLE), INTENT(OUT)         :: YLON(NPTS),YLAT(NPTS),AREA(NPTS)
!#else
! REAL(KIND=C_FLOAT), VALUE, INTENT(IN)    :: FILL
! REAL(KIND=C_FLOAT), INTENT(INOUT)        :: XPTS(NPTS),YPTS(NPTS),RLON(NPTS),RLAT(NPTS)
! REAL(KIND=C_FLOAT), INTENT(OUT)          :: CROT(NPTS),SROT(NPTS),XLON(NPTS),XLAT(NPTS)
! REAL(KIND=C_FLOAT), INTENT(OUT)          :: YLON(NPTS),YLAT(NPTS),AREA(NPTS)
!#endif

 CALL GDSWZD(IGDTNUM,IGDTMPL,IGDTLEN,IOPT,NPTS,FILL, &
             XPTS,YPTS,RLON,RLAT,NRET, &
             CROT,SROT,XLON,XLAT,YLON,YLAT,AREA)

 END SUBROUTINE GDSWZD_C