Add DIAGNOSTICS to alf man page.

1 files changed, 25 insertions, 0 deletions

diff --git a/src/alf.1 b/src/alf.1
index 87d0a36..9198ec4 100644
--- a/src/alf.1
+++ b/src/alf.1
@@ -130,6 +130,31 @@ Success.
 .B 1
 Fatal error (I/O or bad command\-line arguments).
 .UNINDENT
+.SH DIAGNOSTICS
+.sp
+Besides the standard error messages such as "no such file or directory", \fBalf\fP
+can generate warnings about the filenames it\(aqs compressing:
+.INDENT 0.0
+.INDENT 3.5
+.INDENT 0.0
+.TP
+.B \fBfilename has underscore, OK on Sparta/MyDOS, not Atari DOS 2.x\fP
+Not an actual problem, unless you try to extract this ALF file on
+an Atari running Atari DOS 2.0/2.5, or any other DOS that doesn\(aqt
+allow underscores in filenames.
+.TP
+.B \fBbad Atari filename\fP \fI<filename>\fP \fI<reason>\fP
+The filename stored in the ALF header doesn\(aqt follow the rules for
+Atari DOS filenames. \fI<reason>\fP will be something like "doesn\(aqt start
+with A\-Z" or "invalid character". The filename will be printed with
+any unprintable characters as hex values (e.g. \fB$01\fP).
+.UNINDENT
+.UNINDENT
+.UNINDENT
+.sp
+The resulting \fIALF\fP archive will extract with \fBunalf\fP, but will have
+problems with \fBDZ.COM\fP running on an Atari. Or you can just rename
+the files so they comply with Atari DOS filename restrictions.
 .SH NOTES
 .SS Compatibility
 .sp