# HG changeset patch
# User John W. Eaton <jwe@octave.org>
# Date 1347342468 14400
# Node ID 9ed4fc294f3f9df51be4d0a6541d6ba78e4ab690
# Parent  6bdf379592d91fe2cb153b1708843c11ec397a7f
when writing sparse matrices to MAT files, use nzmax of at least 1 (bug #36603)

* ls-mat5.cc (save_mat5_binary_element): If nnz is 0, write 1 for
nzmax in array flags element.

diff --git a/libinterp/interp-core/ls-mat5.cc b/libinterp/interp-core/ls-mat5.cc
--- a/libinterp/interp-core/ls-mat5.cc
+++ b/libinterp/interp-core/ls-mat5.cc
@@ -2429,6 +2429,10 @@
     }
 
   os.write (reinterpret_cast<char *> (&flags), 4);
+  // Matlab seems to have trouble reading files that have nzmax == 0 at
+  // this point in the file.
+  if (nnz_32 == 0)
+    nnz_32 = 1;
   os.write (reinterpret_cast<char *> (&nnz_32), 4);
 
   write_mat5_tag (os, miINT32, dim_len);