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 5e52259df8a64e71bdb230b831485d2a6eae1272..cfe597213768313b6c77030d0e99b619141fd429 100644 (file)
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -159,6 +159,11 @@ void
 slashUsage(unsigned short int pager)
 {
    FILE       *output;
+   char       *currdb;
+
+   currdb = PQdb(pset.db);
+   if (currdb == NULL)
+       currdb = _("none");
 
    output = PageOutput(69, pager);
 
@@ -171,7 +176,7 @@ slashUsage(unsigned short int pager)
    fprintf(output, _("General\n"));
    fprintf(output, _("  \\c[onnect] [DBNAME|- USER|- HOST|- PORT|-]\n"
            "                 connect to new database (currently \"%s\")\n"),
-           PQdb(pset.db));
+           currdb);
    fprintf(output, _("  \\cd [DIR]      change the current working directory\n"));
    fprintf(output, _("  \\copyright     show PostgreSQL usage and distribution terms\n"));
    fprintf(output, _("  \\encoding [ENCODING]\n"