2022.03.20

doc/CHANGES

@@ -14661,4 +14661,43 @@ if (strstr(line,"%%begintext") != NULL) {
 which returns the pointer to %%begintext in the line.
 
 
+March 20 2022
+
+abc2midi bug: I could not demonstrate this bug on my own system.
+
+When abc2midi is compiled on a Debian linux system using the -O2 compilation
+flag (by default), it produces a faulty midi file for abc files containing
+gchords. Here is a sample file.
+
+%abc-2.2
+X:1
+T:Test
+M:C
+L:1/4
+Q:1/4=135
+V:S clef=treble
+V:s clef=treble
+K:C
+%%score (s S)
+%
+[V:s] "C" x2 "a" x2 |
+[V:S]  C  C   A A   |
+
+The problem occurs with the bass accompaniment generated by "a". The
+bass accompaniment creates a long string of A,, notes.
+
+This problem disappears when abc2midi is compiled without the
+-O2 optimizer.
+
+Analysis: the bug was traced to the code gchord_configure in genmidi.c.
+The limit of the loops
+ for (j=0; j<chordlen[chordnum]; j++)
+contain bad data when chordnum is set to -1 (for bass accompaniment).
+
+Fix: exit from gchord_configure function when chordnum is less than
+zero.
+
+The problem was identified to me by Jakob Englhauser. Jakob verified
+that this fix works.
+