diff --git a/epan/column-utils.c b/epan/column-utils.c
index 8851fce7f1..2505e6dff7 100644
--- a/epan/column-utils.c
+++ b/epan/column-utils.c
@@ -191,7 +191,7 @@ col_clear(column_info *cinfo, gint el)
 /* Use this if "str" points to something that will stay around (and thus
    needn't be copied). */
 void
-col_set_str(column_info *cinfo, gint el, gchar* str)
+col_set_str(column_info *cinfo, gint el, const gchar* str)
 {
   int i;
   int fence;
@@ -338,11 +338,11 @@ col_append_sep_fstr(column_info *cinfo, gint el, const gchar *separator,
 void
 col_prepend_fstr(column_info *cinfo, gint el, const gchar *format, ...)
 {
-  va_list ap;
-  int     i;
-  char    orig_buf[COL_BUF_MAX_LEN];
-  char   *orig;
-  size_t  max_len;
+  va_list     ap;
+  int         i;
+  char        orig_buf[COL_BUF_MAX_LEN];
+  const char *orig;
+  size_t      max_len;
 
   g_assert(cinfo->col_first[el] >= 0);
   if (el == COL_INFO)
@@ -354,12 +354,12 @@ col_prepend_fstr(column_info *cinfo, gint el, const gchar *format, ...)
   for (i = cinfo->col_first[el]; i <= cinfo->col_last[el]; i++) {
     if (cinfo->fmt_matx[i][el]) {
       if (cinfo->col_data[i] != cinfo->col_buf[i]) {
-      	/* This was set with "col_set_str()"; which is effectively const */
+        /* This was set with "col_set_str()"; which is effectively const */
         orig = cinfo->col_data[i];
       } else {
+        strncpy(orig_buf, cinfo->col_buf[i], max_len);
+        orig_buf[max_len - 1] = '\0';
         orig = orig_buf;
-	strncpy(orig, cinfo->col_buf[i], max_len);
-	orig[max_len - 1] = '\0';
       }
       vsnprintf(cinfo->col_buf[i], max_len, format, ap);
       cinfo->col_buf[i][max_len - 1] = '\0';
diff --git a/epan/column_info.h b/epan/column_info.h
index 85eff842e0..69c631afc7 100644
--- a/epan/column_info.h
+++ b/epan/column_info.h
@@ -31,18 +31,18 @@
 #define COL_MAX_INFO_LEN 4096
 
 typedef struct _column_info {
-  gint       num_cols;  /* Number of columns */
-  gint      *col_fmt;   /* Format of column */
-  gboolean **fmt_matx;  /* Specifies which formats apply to a column */
-  gint      *col_first; /* First column number with a given format */
-  gint      *col_last;  /* Last column number with a given format */
-  gchar    **col_title; /* Column titles */
-  gchar    **col_data;  /* Column data */
-  gchar    **col_buf;   /* Buffer into which to copy data for column */
-  int      *col_fence;  /* Stuff in column buffer before this index is immutable */
-  gchar    **col_expr;  /* Filter expression */
-  gchar    **col_expr_val;  /* Value for filter expression */
-  gboolean   writable;  /* Are we stil writing to the columns? */
+  gint          num_cols;    /* Number of columns */
+  gint         *col_fmt;     /* Format of column */
+  gboolean    **fmt_matx;    /* Specifies which formats apply to a column */
+  gint         *col_first;   /* First column number with a given format */
+  gint         *col_last;    /* Last column number with a given format */
+  gchar       **col_title;   /* Column titles */
+  const gchar **col_data;    /* Column data */
+  gchar       **col_buf;     /* Buffer into which to copy data for column */
+  int         *col_fence;    /* Stuff in column buffer before this index is immutable */
+  gchar      **col_expr;     /* Filter expression */
+  gchar      **col_expr_val; /* Value for filter expression */
+  gboolean     writable;     /* Are we stil writing to the columns? */
 } column_info;
 
 /*
diff --git a/gtk/packet_win.c b/gtk/packet_win.c
index 5d5dae16a5..427b4fe9d1 100644
--- a/gtk/packet_win.c
+++ b/gtk/packet_win.c
@@ -95,7 +95,7 @@ void new_window_cb(GtkWidget *w _U_)
 {
 #define NewWinTitleLen 1000
   char Title[NewWinTitleLen] = "";
-  char *TextPtr;
+  const char *TextPtr;
   gint tv_size = 95, bv_size = 75;
   GtkWidget *main_w, *main_vbox, *pane,
                       *tree_view, *tv_scrollw,
diff --git a/print.c b/print.c
index d1ffd14cb2..a95e3c859b 100644
--- a/print.c
+++ b/print.c
@@ -76,7 +76,7 @@ static gboolean print_hex_data_buffer(print_stream_t *stream, const guchar *cp,
     guint length, char_enc encoding);
 static void ps_clean_string(unsigned char *out, const unsigned char *in,
 			int outbuf_size);
-static void print_escaped_xml(FILE *fh, char *unescaped_string);
+static void print_escaped_xml(FILE *fh, const char *unescaped_string);
 
 static void print_pdml_geninfo(proto_tree *tree, FILE *fh);
 
@@ -561,9 +561,9 @@ get_field_data(GSList *src_list, field_info *fi)
 /* Print a string, escaping out certain characters that need to
  * escaped out for XML. */
 static void
-print_escaped_xml(FILE *fh, char *unescaped_string)
+print_escaped_xml(FILE *fh, const char *unescaped_string)
 {
-	unsigned char *p;
+	const unsigned char *p;
 
 	for (p = unescaped_string; *p != '\0'; p++) {
 		switch (*p) {