From 532914dd600a7455c6667cd249065a5e5c9cc6b7 Mon Sep 17 00:00:00 2001
From: Benjamin Greiner <code@bnavigator.de>
Date: Sun, 17 May 2020 17:32:04 +0200
Subject: [PATCH] [skip ci] [WIP] override xerbla to raise exception

---
 slycot/CMakeLists.txt   |  2 +-
 slycot/__init__.py      |  5 +++++
 slycot/exceptions.py    |  8 ++++++++
 slycot/src/XERBLA.f     | 19 +++++++++++++++++++
 slycot/src/_helper.pyf  |  9 +++++++--
 slycot/src/_wrapper.pyf | 25 ++++++++++++++++++-------
 6 files changed, 58 insertions(+), 10 deletions(-)
 create mode 100644 slycot/src/XERBLA.f

diff --git a/slycot/CMakeLists.txt b/slycot/CMakeLists.txt
index c481cea6..140e89a2 100644
--- a/slycot/CMakeLists.txt
+++ b/slycot/CMakeLists.txt
@@ -104,7 +104,7 @@ set(FSOURCES
     src/delctg.f  src/select.f
     src/SLCT_DLATZM.f  src/SLCT_ZLATZM.f
 
-    src/ftruefalse.f
+    src/ftruefalse.f src/XERBLA.f
 )
 
 set(F2PYSOURCE src/_wrapper.pyf)
diff --git a/slycot/__init__.py b/slycot/__init__.py
index 0c2b3c70..1b344e49 100644
--- a/slycot/__init__.py
+++ b/slycot/__init__.py
@@ -43,6 +43,11 @@
     # Version information
     from .version import version as __version__
 
+    # initialize error handling
+    from .exceptions import raise_xerbla
+    from . import _wrapper
+    _wrapper.raise_xerbla = raise_xerbla
+
     from numpy.testing import Tester
     test = Tester().test
     bench = Tester().bench
diff --git a/slycot/exceptions.py b/slycot/exceptions.py
index f08bb3f6..7376e6e2 100644
--- a/slycot/exceptions.py
+++ b/slycot/exceptions.py
@@ -257,3 +257,11 @@ def raise_if_slycot_error(info, arg_list=None, docstring=None, checkvars=None):
         warn(SlycotWarning("Caught unhandled nonzero IWARN value {}"
                            "".format(iwarn),
                            iwarn, info))
+
+
+def raise_xerbla(srname, info):
+    """Overrides LAPACK XERBLA routine to raise Exception instead of exiting
+    """
+    message = ("The argument number {1} to {0} had an illegal value."
+               "".format(srname, -info))
+    raise SlycotParameterError(message, info)
diff --git a/slycot/src/XERBLA.f b/slycot/src/XERBLA.f
new file mode 100644
index 00000000..067867c6
--- /dev/null
+++ b/slycot/src/XERBLA.f
@@ -0,0 +1,19 @@
+      SUBROUTINE XERBLA(SRNAME, INFO)
+C
+C     SLYCOT
+C     Override LAPACK XERBLA routine to raise Python Exception instead of
+C     exiting the process
+C
+CF2PY INTENT(CALLBACK, HIDE) RAISE_XERBLA
+C
+      CHARACTER*(*) SRNAME
+      INTEGER INFO
+C
+      EXTERNAL RAISE_XERBLA
+C
+      CALL RAISE_XERBLA(SRNAME, INFO)
+C
+      RETURN
+C
+      END
+C
\ No newline at end of file
diff --git a/slycot/src/_helper.pyf b/slycot/src/_helper.pyf
index ed59e106..ac97e723 100644
--- a/slycot/src/_helper.pyf
+++ b/slycot/src/_helper.pyf
@@ -6,5 +6,10 @@ subroutine ftruefalse(ftrue,ffalse) ! in src/ftruefalse.f
     logical intent(out) :: ffalse
 end subroutine ftruefalse
 
-! This file was auto-generated with f2py (version:2).
-! See http://cens.ioc.ee/projects/f2py2e/
+subroutine xerbla(srname,info) ! in src/XERBLA.f
+    use __user__routines
+    character*(*) :: srname
+    integer :: info
+    intent(callback) raise_xerbla
+    external raise_xerbla
+end subroutine xerbla
diff --git a/slycot/src/_wrapper.pyf b/slycot/src/_wrapper.pyf
index 5a4c6784..e5518ef7 100644
--- a/slycot/src/_wrapper.pyf
+++ b/slycot/src/_wrapper.pyf
@@ -1,12 +1,23 @@
 !    -*- f90 -*-
 ! Note: the context of this file is case sensitive.
 
-python module _wrapper ! in
-    interface  ! in :wrapper
-		include "analysis.pyf"
-		include "math.pyf"
-		include "synthesis.pyf"
-		include "transform.pyf"
-		include "_helper.pyf"
+python module __user__routines
+    interface
+        subroutine raise_xerbla(srname,info)
+            intent(callback,hide) raise_xerbla
+            character*(*) :: srname
+            integer :: info
+        end subroutine raise_xerbla
+    end interface
+end python module __user__routines
+
+python module _wrapper
+    interface
+        include "analysis.pyf"
+        include "math.pyf"
+        include "synthesis.pyf"
+        include "transform.pyf"
+        include "_helper.pyf"
     end interface
 end python module slycot
+