Don't pass NULL to fprintf, if not currently connected to a database.

Backpatch all the way to 8.3. Fixes bug #7811, per report and diagnosis by
Meng Qingzhong.

diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index ac5edca65dd42a37531f8d8bf84afdbcaae33eda..ccbd542c61703dc0475051197242f274bf9d6714 100644 (file)
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -157,6 +157,11 @@ void
 slashUsage(unsigned short int pager)
 {
        FILE       *output;
+       char       *currdb;
+
+       currdb = PQdb(pset.db);
+       if (currdb == NULL)
+               currdb = _("none");
 
        output = PageOutput(92, pager);
 
@@ -248,7 +253,7 @@ slashUsage(unsigned short int pager)
        fprintf(output, _("Connection\n"));
        fprintf(output, _("  \\c[onnect] [DBNAME|- USER|- HOST|- PORT|-]\n"
        "                         connect to new database (currently \"%s\")\n"),
-                       PQdb(pset.db));
+                       currdb);
        fprintf(output, _("  \\encoding [ENCODING]   show or set client encoding\n"));
        fprintf(output, _("  \\password [USERNAME]   securely change the password for a user\n"));
        fprintf(output, _("  \\conninfo              display information about current connection\n"));