Avoid cryptic message when survey's first argument is empty

Catch empty argument instead of letting nstr_comp_val() choke on it.

diff --git a/src/lib/commands/surv.c b/src/lib/commands/surv.c
index d3a27e8dcdba847f9e42335caba2b1dc2a9e4507..92117a7d8846a858c094c8d915f072d947de14d1 100644 (file)
--- a/src/lib/commands/surv.c
+++ b/src/lib/commands/surv.c
@@ -66,7 +66,7 @@ surv(void)
 
     nsect = 0;
     ptr = getstarg(player->argp[1], "commodity or variable? ", buf);
-    if (ptr == 0)
+    if (!ptr || !*ptr)
        return RET_SYN;
     ptr = nstr_comp_val(ptr, &val, EF_SECTOR);
     if (!ptr)