1 files changed, 8 insertions, 7 deletions

diff --git a/src/lib_string.c b/src/lib_string.c
index d1a60b61..c1e595c9 100644
--- a/src/lib_string.c
+++ b/src/lib_string.c
@@ -850,20 +850,21 @@ LJLIB_CF(string_format)
     } else { /* format item */
       char form[MAX_FMTSPEC];  /* to store the format (`%...') */
       char buff[MAX_FMTITEM];  /* to store the formatted item */
+      int n = 0;
       if (++arg > top)
         luaL_argerror(L, arg, lj_obj_typename[0]);
       strfrmt = scanformat(L, strfrmt, form);
       switch (*strfrmt++) {
       case 'c':
-        sprintf(buff, form, lj_lib_checkint(L, arg));
+        n = sprintf(buff, form, lj_lib_checkint(L, arg));
         break;
       case 'd':  case 'i':
         addintlen(form);
-        sprintf(buff, form, num2intfrm(L, arg));
+        n = sprintf(buff, form, num2intfrm(L, arg));
         break;
       case 'o':  case 'u':  case 'x':  case 'X':
         addintlen(form);
-        sprintf(buff, form, num2uintfrm(L, arg));
+        n = sprintf(buff, form, num2uintfrm(L, arg));
         break;
       case 'e':  case 'E': case 'f': case 'g': case 'G': case 'a': case 'A': {
         TValue tv;
@@ -880,10 +881,10 @@ LJLIB_CF(string_format)
           nbuf[len] = '\0';
           for (p = form; *p < 'A' && *p != '.'; p++) ;
           *p++ = 's'; *p = '\0';
-          sprintf(buff, form, nbuf);
+          n = sprintf(buff, form, nbuf);
           break;
         }
-        sprintf(buff, form, (double)tv.n);
+        n = sprintf(buff, form, (double)tv.n);
         break;
         }
       case 'q':
@@ -902,14 +903,14 @@ LJLIB_CF(string_format)
           luaL_addvalue(&b);
           continue;
         }
-        sprintf(buff, form, strdata(str));
+        n = sprintf(buff, form, strdata(str));
         break;
         }
       default:
         lj_err_callerv(L, LJ_ERR_STRFMTO, *(strfrmt -1));
         break;
       }
-      luaL_addlstring(&b, buff, strlen(buff));
+      luaL_addlstring(&b, buff, n);
     }
   }
   luaL_pushresult(&b);