Check for wildcards matching *.alf; generally this is an error.

3 files changed, 26 insertions, 1 deletions

diff --git a/src/opts.c b/src/opts.c
index 3120317..3237642 100644
--- a/src/opts.c
+++ b/src/opts.c
@@ -27,6 +27,7 @@ static void show_globs(void) {
 
 void parse_opts(int argc, char * const *argv) {
 	int opt;
+	char **ig;
 
 	while((opt = getopt(argc, argv, OPTIONS)) != -1) {
 		switch(opt) {
@@ -55,7 +56,17 @@ void parse_opts(int argc, char * const *argv) {
 	}
 
 	in_filename = argv[optind];
-	include_globs = &argv[optind + 1]; /* might be null, that's OK */
+	if(optind < argc)
+		include_globs = &argv[optind + 1]; /* might be null, that's OK */
+
+	ig = (char **)include_globs;
+	while(*ig) {
+		if(globmatch("*.alf", *ig)) {
+			fprintf(stderr, "%s: ALF files don't normally contain other ALF files, are you trying to extract/list multiple ALF files at once?\n", self);
+			break;
+		}
+		ig++;
+	}
 
 #ifdef DEBUG_GLOBS
 	show_globs();
diff --git a/src/unalf.1 b/src/unalf.1
index 383974c..7d7615c 100644
--- a/src/unalf.1
+++ b/src/unalf.1
@@ -301,6 +301,13 @@ that big.
 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 \fBALF files don\(aqt normally contain other ALF files, are you trying to extract/list multiple ALF files at once?\fP
+You gave a \fIwildcard\fP argument that ends with \fI\&.alf\fP\&. This is OK if
+your \fIALF\fP file actually contains another \fIALF\fP file, but that would
+be a pathological case. Most likely, you\(aqre trying to extract multiple
+\fIALF\fP files with one command, which doesn\(aqt work. Use one \fBunalf\fP
+command per file.
 .UNINDENT
 .SH NOTES
 .sp
diff --git a/src/unalf.rst b/src/unalf.rst
index 32a3982..7ba2f0a 100644
--- a/src/unalf.rst
+++ b/src/unalf.rst
@@ -256,6 +256,13 @@ Besides the standard error messages such as "no such file or directory":
   an Atari running Atari DOS 2.0/2.5, or any other DOS that doesn't
   allow underscores in filenames.
 
+**ALF files don't normally contain other ALF files, are you trying to extract/list multiple ALF files at once?**
+  You gave a *wildcard* argument that ends with *.alf*. This is OK if
+  your *ALF* file actually contains another *ALF* file, but that would
+  be a pathological case. Most likely, you're trying to extract multiple
+  *ALF* files with one command, which doesn't work. Use one **unalf**
+  command per file.
+
 NOTES
 =====