Review issues.

Signed-off-by: Michal Zientkiewicz <michalz@nvidia.com>

Author: mzient

dali/c_api_2/pipeline.cc

@@ -609,7 +609,7 @@ void AddArgToSpec(dali::OpSpec &spec, const daliArgDesc_t &arg) {
       std::vector<std::string> sv;
       sv.reserve(arg.size);
       for (int64_t i = 0; i < arg.size; i++) {
-        if (!d[i])
+        if (!d[i])  // the outer `if` prevents make_string in case of no error
           check_not_null(d[i], dali::make_string("arg.arr[", i, "]"));
         sv.emplace_back(d[i]);
       }
@@ -703,6 +703,10 @@ daliResult_t daliPipelineSetOutputs(
       const daliPipelineIODesc_t *outputs) {
   DALI_PROLOG();
   auto pipe = ToPointer(pipeline);
+  dali::c_api::CheckArg(num_outputs >= 0, "`num_outputs` must not be negative");
+  if (num_outputs == 0)
+    return DALI_SUCCESS;  // nothing to do
+
   NOT_NULL(outputs);
   std::vector<dali::PipelineOutputDesc> descs;
   descs.reserve(num_outputs);

include/dali/dali.h

@@ -380,7 +380,6 @@ typedef struct _DALIArgInputDesc {
  *   - DALI_INT8..DALI_INT64   -> ivalue
  *   - DALI_UINT8..DALI_UINT64 -> uvalue
  *   - DALI_FLOAT              -> fvalue
- *   - DALI_FLOAT64            -> dvalue
  *   - DALI_BOOL               -> ivalue (0 = false, non-zero = true)
  *   - DALI_STRING             -> str (NULL-terminated)
  *
@@ -390,7 +389,9 @@ typedef struct _DALIArgInputDesc {
  *   - DALI_BOOL_VEC           -> arr points to bool[], size = element count
  *   - DALI_STRING_VEC         -> arr points to const char*[], size = element count
  *
- * For vector types, `arr` must be non-NULL and `size` must be >= 0.
+ * Other types (including DALI_FLOAT64) are not supported.
+ *
+ * For vector types, `size` must be >= 0 and `arr` must be non-NULL when `size` > 0.
  */
 typedef struct _DALIArgDesc {
   const char     *name;