diff --git a/C_C++/flex/segv_issue.l b/C_C++/flex/segv_issue.l
new file mode 100644
index 0000000..49057bd
--- /dev/null
+++ b/C_C++/flex/segv_issue.l
@@ -0,0 +1,60 @@
+/* @BAKE
+    flex -o $*.c $@
+    cc -o eof $*.c -ggdb -lfl
+   @STOP
+*/
+ALPHABETIC  [a-zA-Z]
+WS          [^a-zA-Z!]
+
+%option
+
+%%
+
+{ALPHABETIC}+   {
+    ECHO;
+    return 1;
+}
+{WS}+   {
+    ECHO;
+    return 2;
+}
+
+"!"         {
+    char buf[80];
+    for (int idx=0; (buf[idx] = input()); idx++) /* empty */ ;
+    printf("buf=<%s>\n", buf);
+    // YY_FLUSH_BUFFER; /* makes no difference */
+    return 3;
+    ECHO;
+    char c;
+    while (c = input()) {
+        printf("'%c'\n", c);
+    }
+    return 3;
+}
+
+%%
+int main(int argc, const char * const * const argv)
+{
+    /*
+    switch (argc) {
+      case 1: break;
+      case 2:
+        yy_scan_string(argv[1]);
+        break;
+      default:
+        fprintf(stderr, "Usage: %s [string]\n", argv[0]);
+        exit(1);
+    }
+    */
+
+    const char * test = "one two !three four";
+    yy_scan_string(argv[1]);
+
+
+    int token;
+    while ((token = yylex()) != 0) {
+        printf("-> %d\n", token);
+        fflush(stdout);
+    }
+}