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Information in this article applies to:

  • C51 All Versions


I have recently tried this code snippet:

#include <stdio.h>

typedef enum
   ENQ_IDLE = 0,
} UDE_enq_cmd_state_t;

enum UDE_enq_cmd_state_t {

   ENQ_IDLE = 0,
typedef enum UDE_enq_cmd_state_t EnqCmdState;

UDE_enq_cmd_state_t EnqCmdState;

void main(void)
unsigned char testy;

EnqCmdState = ENQ_IDLE;
EnqCmdState = 15;



and it compiles and links with no errors or warnings.

Normally, I would expect an error on the line: EnqCmdState = 15; otherwise using the typedef is a bit of a waste of time. How do I use this to write more defensive programming?


It is legal in C to assign an 'enum' variable a constant value. Several embedded compilers support this, as does Microsoft Visual C. Code checking tools such as PC-LINT will flag code that attempts to assign constants to an enum.

Last Reviewed: Tuesday, March 8, 2011

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