1 files changed, 64 insertions, 0 deletions
diff --git a/doc/m4.texi b/doc/m4.texi
index f262a7b4..801f9f94 100644
--- a/doc/m4.texi
+++ b/doc/m4.texi
@@ -1129,6 +1129,70 @@ If you need to read a file whose name starts with a @file{-}, you can
 specify it as @samp{./-file}, or use @option{--} to mark the end of
 options.
 
+@ignore
+@comment Test that 'm4 file/' detects that file is not a directory; we
+@comment can assume that the current directory contains a Makefile.
+@comment mingw fails with EINVAL rather than ENOTDIR.
+
+@comment status: 1
+@comment xerr: ignore
+@comment options: Makefile/
+@example
+@error{}m4: cannot open file 'Makefile/': No such file or directory
+@end example
+
+@comment Test that closed stderr does not cause a crash.  Not all
+@comment systems have the same message for EBADF.
+
+@comment xerr: ignore
+@example
+ifdef(`__unix__', ,
+      `errprint(` skipping: syscmd does not have unix semantics
+')m4exit(`77')')dnl
+syscmd(`echo | cat >&- 2>/dev/null')ifelse(sysval, `0',
+       `errprint(` skipping: system does not allow closing stdout
+')m4exit(`77')')dnl
+changequote(`[', `]')dnl
+syscmd([echo | ']__program__[' >&-])dnl
+@error{}m4: write error: Bad file descriptor
+sysval
+@result{}1
+@end example
+
+@example
+ifdef(`__unix__', ,
+      `errprint(` skipping: syscmd does not have unix semantics
+')m4exit(`77')')dnl
+syscmd(`echo | cat >&- 2>/dev/null')ifelse(sysval, `0',
+       `errprint(` skipping: system does not allow closing stdout
+')m4exit(`77')')dnl
+changequote(`[', `]')dnl
+syscmd([echo 'esyscmd(echo hi >&2 && echo err"print(bye
+)d"nl)dnl' > tmp.m4 \
+  && ']__program__[' tmp.m4 <&- >&- \
+  && rm tmp.m4])sysval
+@error{}hi
+@error{}bye
+@result{}0
+@end example
+
+@comment Test that we obey POSIX semantics with -D interspersed with
+@comment files, even with POSIXLY_CORRECT (BSD getopt gets it wrong).
+
+$ @kbd{m4 }
+@example
+ifdef(`__unix__', ,
+      `errprint(` skipping: syscmd does not have unix semantics
+')m4exit(`77')')dnl
+changequote(`[', `]')dnl
+syscmd([POSIXLY_CORRECT=1 ']__program__[' -Dbar=hello foo -Dbar=world foo])dnl
+@result{}hello
+@result{}world
+sysval
+@result{}0
+@end example
+@end ignore
+
 @node Syntax
 @chapter Lexical and syntactic conventions