text: //------------------------------------------------------------------------------
  // GB_SelectOp_check: check and print a select operator
  //------------------------------------------------------------------------------
  
  // SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2020, All Rights Reserved.
  // http://suitesparse.com   See GraphBLAS/Doc/License.txt for license.
  
  //------------------------------------------------------------------------------
  
  #include "GB_printf.h"
  
  GrB_Info GB_SelectOp_check  // check a GraphBLAS select operator
  (
      const GxB_SelectOp op,  // GraphBLAS operator to print and check
      const char *name,       // name of the operator
      int pr,                 // 0: print nothing, 1: print header and errors,
                              // 2: print brief, 3: print all
      FILE *f,                // file for output
      GB_Context Context
  )
  {
  
      //--------------------------------------------------------------------------
      // check inputs
      //--------------------------------------------------------------------------
  
      GBPR0 ("\n    GraphBLAS SelectOp: %s: ", GB_NAME) ;
  
      if (op == NULL)
      { 
          // GrB_error status not modified since this may be an optional argument
          GBPR0 ("NULL\n") ;
          return (GrB_NULL_POINTER) ;
      }
  
      //--------------------------------------------------------------------------
      // check object
      //--------------------------------------------------------------------------
  
      GB_CHECK_MAGIC (op, "SelectOp") ;
  
      if (pr > 0)
      {
          if (op->opcode >= GB_USER_SELECT_opcode)
          { 
              GBPR ("(user-defined) ") ;
          }
          else
          { 
              GBPR ("(built-in) ") ;
          }
      }
  
      GBPR0 ("C=%s(A,k)\n", op->name) ;
  
      if (op->function == NULL && op->opcode >= GB_USER_SELECT_opcode)
      { 
          GBPR0 ("    function pointer is NULL\n") ;
          return (GB_ERROR (GrB_INVALID_OBJECT, (GB_LOG,
              "SelectOp has a NULL function pointer: %s [%s]",
              GB_NAME, op->name))) ;
      }
  
      if (op->opcode < GB_TRIL_opcode || op->opcode > GB_USER_SELECT_opcode)
      { 
          GBPR0 ("    invalid opcode\n") ;
          return (GB_ERROR (GrB_INVALID_OBJECT, (GB_LOG,
              "SelectOp has an invalid opcode: %s [%s]", GB_NAME, op->name))) ;
      }
  
      if (op->xtype != NULL)
      { 
          GrB_Info info = GB_Type_check (op->xtype, "xtype", pr, f, Context) ;
          if (info != GrB_SUCCESS)
          { 
              GBPR0 ("    SelectOp has an invalid xtype\n") ;
              return (GB_ERROR (GrB_INVALID_OBJECT, (GB_LOG,
                  "SelectOp has an invalid xtype: %s [%s]", GB_NAME, op->name))) ;
          }
      }
  
      if (op->ttype != NULL)
      { 
          GrB_Info info = GB_Type_check (op->ttype, "ttype", pr, f, Context) ;
          if (info != GrB_SUCCESS)
          { 
              GBPR0 ("    SelectOp has an invalid ttype\n") ;
              return (GB_ERROR (GrB_INVALID_OBJECT, (GB_LOG,
                  "SelectOp has an invalid ttype: %s [%s]", GB_NAME, op->name))) ;
          }
      }
  
      return (GrB_SUCCESS) ;
  }
  
  