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 47fa934db53df4dee05951dda3d4c9d1e880dcba..213b87c5393f5c69376fa67219a60b4603fea5cf 100644 (file)
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -161,6 +161,11 @@ void
 slashUsage(unsigned short int pager)
 {
    FILE       *output;
+   char       *currdb;
+
+   currdb = PQdb(pset.db);
+   if (currdb == NULL)
+       currdb = _("none");
 
    output = PageOutput(86, pager);
 
@@ -246,7 +251,7 @@ 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, "\n");