c - What does the warning - expected ‘struct node **’ but argument is of type ‘struct node **’ mean? -

my code tree creation array:

#include<stdio.h> #include<malloc.h> typedef struct {     struct node* left;     struct node* right;     int val; }node;  void create_tree(node** root,int val) {      if(*root == null )     {         *root = (node*)malloc(sizeof(node));         (*root)->val = val;         (*root)->left = null;         (*root)->right = null;         return;     }        if((*root)->val <= val )         create_tree(&((*root)->left),val);     else         create_tree(&((*root)->right),val);      return ;     }    int main() {     node *root = (node*)malloc(sizeof(node));     root->val = 10;     root->left = null;     root->right = null;     int val[] = { 11,16,6,20,19,8,14,4,0,1,15,18,3,13,9,21,5,17,2,7,12};     int i;     for(i=0;i<22;i++)            create_tree(&root,val[i]);     return 0; } 

warning getting:

tree.c:10:6: note: expected ‘struct node **’ argument of type ‘struct node **’  void create_tree(node** root,int val)       ^ 

i not able understand warning say? both expected , actual of type struct node **. bug?

after edit (that's why ask [mcve]), clear problem is.

inside struct, reference struct node. not define type, define alias node struct has no name itself.

note in c struct node resides in different namespace "normal" names variables or typedefed aliases.

so have add tag:

typedef struct node {     struct node* left;     struct node* right;     int val; } node; 

that way have struct node type name node.