BUG: ensure raising a ValueError if return -1 (#788)

The C function surf_import_ijxyz_tmpl may return -1
which means that using a template fails. Earlier this
was not handled; now a ValueError is raised in the
receiving python code. Context: Auto4D bug report.

src/clib/xtg/surf_import_ijxyz_tmpl.c

@@ -114,8 +114,7 @@ surf_import_ijxyz_tmpl(FILE *fd,
         /* some sanity tests first */
         if (iline < ilines[0] || iline > ilines[nncol - 1] || xline < xlines[0] ||
             xline > xlines[nnrow - 1]) {
-            logger_error(LI, FI, FU, "ILINE or XLINE in file outside template ranges");
-            return -1;
+            return -1;  // handle this code as error in client
         }
 
         found = 0;

src/xtgeo/surface/_regsurf_import.py

@@ -3,17 +3,16 @@
 
 import json
 from collections import OrderedDict
+from struct import unpack
 
+import h5py
 import numpy as np
 import numpy.ma as ma
-from struct import unpack
-import h5py
-
-from xtgeo.common.constants import UNDEF_MAP_IRAPB, UNDEF_MAP_IRAPA
 import xtgeo
 import xtgeo.common.sys as xsys
 import xtgeo.cxtgeo._cxtgeo as _cxtgeo  # pylint: disable=no-name-in-module
 from xtgeo.common import XTGeoDialog
+from xtgeo.common.constants import UNDEF_MAP_IRAPA, UNDEF_MAP_IRAPB
 from xtgeo.surface._zmap_parser import parse_zmap
 
 xtg = XTGeoDialog()
@@ -331,10 +330,20 @@ def _import_ijxyz_tmpl(mfile, template):
         raise ValueError("Template is of wrong type: {}".format(type(template)))
 
     nxy = template.ncol * template.nrow
-    _, val = _cxtgeo.surf_import_ijxyz_tmpl(
+    ier, val = _cxtgeo.surf_import_ijxyz_tmpl(
         cfhandle, template.ilines, template.xlines, nxy, 0
     )
 
+    if ier == -1:
+        raise ValueError(
+            f"The file {mfile.name} and template map or cube has inconsistent "
+            "inline and/or xlines numbering. Try importing without template "
+            "and use e.g. resampling instead."
+        )
+
+    elif ier != 0:
+        raise RuntimeError("Unknown error when trying to import the IJXYZ based file!")
+
     val = ma.masked_greater(val, xtgeo.UNDEF_LIMIT)
 
     args = {}