Refine the error logs.

paddle/capi/examples/model_inference/common/common.h

@@ -7,14 +7,17 @@
   do {                                                                   \
     paddle_error __err__ = stmt;                                         \
     if (__err__ != kPD_NO_ERROR) {                                       \
-      fprintf(stderr, "Invoke paddle error %d \n" #stmt, __err__); \
+      fprintf(stderr, "Invoke paddle error %d in " #stmt "\n", __err__); \
       exit(__err__);                                                     \
     }                                                                    \
   } while (0)
 
 void* read_config(const char* filename, long* size) {
   FILE* file = fopen(filename, "r");
-  if (file == NULL) return NULL;
+  if (file == NULL) {
+    fprintf(stderr, "Open %s error\n", filename);
+    return NULL;
+  }
   fseek(file, 0L, SEEK_END);
   *size = ftell(file);
   fseek(file, 0L, SEEK_SET);