Enumerated Type Not Comparing Correctly
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Hello. I'm writing some C code for an embedded application, and I've run into a problem wherein a compare against an enumerated value is not being executed correctly. Take the following code snippet, for example:
typedef unsigned int UINT16;
typedef enum enum_items_tag
{
ITEM_1,
ITEM_2,
ITEM_3,/* ... */
ITEM_918,
MAX_ENUM_ITEMS
} enum_items_t;UINT16 n;
for ( n = 0; n < MAX_ENUM_ITEMS; n++ )
{
// Do something
}The code executes as expected, until n is incremented to equal MAX_ENUM_ITEMS, at which time the compare fails, and execution continues within the loop (when it should have exited). I've done things like this in the past without any problems. I've tried re-typing n as enum_items_t (i.e. declaring n as "enum_items_t n"), as well as type casting MAX_ENUM_ITEMS as UINT16. The only other thing I can think of at this point is that maybe there is an issue with the number of items there are in my enumerated type (919). Does anyone know if there are such constraints on enumerated types? I'm using a GCC based compiler. Or, if you have any other ideas, it would be much appreciated. Thanks.
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Hello. I'm writing some C code for an embedded application, and I've run into a problem wherein a compare against an enumerated value is not being executed correctly. Take the following code snippet, for example:
typedef unsigned int UINT16;
typedef enum enum_items_tag
{
ITEM_1,
ITEM_2,
ITEM_3,/* ... */
ITEM_918,
MAX_ENUM_ITEMS
} enum_items_t;UINT16 n;
for ( n = 0; n < MAX_ENUM_ITEMS; n++ )
{
// Do something
}The code executes as expected, until n is incremented to equal MAX_ENUM_ITEMS, at which time the compare fails, and execution continues within the loop (when it should have exited). I've done things like this in the past without any problems. I've tried re-typing n as enum_items_t (i.e. declaring n as "enum_items_t n"), as well as type casting MAX_ENUM_ITEMS as UINT16. The only other thing I can think of at this point is that maybe there is an issue with the number of items there are in my enumerated type (919). Does anyone know if there are such constraints on enumerated types? I'm using a GCC based compiler. Or, if you have any other ideas, it would be much appreciated. Thanks.
why do not output value of MAX_ENUM_ITEMS to see what it is, you may miss some thing in the middle of the enum. totally 919 items? MAX_ENUM_ITEMS should be 918.
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why do not output value of MAX_ENUM_ITEMS to see what it is, you may miss some thing in the middle of the enum. totally 919 items? MAX_ENUM_ITEMS should be 918.
You're right. Good catch! The enumerated type enum_items_t has a total of 920 items, including MAX_ENUM_ITEMS. I was thinking in terms of offset, or what n would be as the loop repeats. Unfortunately, outputting constants information with embedded programming can be a little tricky, especially when you're stuck using a ***** compiler/IDE. I'll see what I can do, though. Thanks.
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Hello. I'm writing some C code for an embedded application, and I've run into a problem wherein a compare against an enumerated value is not being executed correctly. Take the following code snippet, for example:
typedef unsigned int UINT16;
typedef enum enum_items_tag
{
ITEM_1,
ITEM_2,
ITEM_3,/* ... */
ITEM_918,
MAX_ENUM_ITEMS
} enum_items_t;UINT16 n;
for ( n = 0; n < MAX_ENUM_ITEMS; n++ )
{
// Do something
}The code executes as expected, until n is incremented to equal MAX_ENUM_ITEMS, at which time the compare fails, and execution continues within the loop (when it should have exited). I've done things like this in the past without any problems. I've tried re-typing n as enum_items_t (i.e. declaring n as "enum_items_t n"), as well as type casting MAX_ENUM_ITEMS as UINT16. The only other thing I can think of at this point is that maybe there is an issue with the number of items there are in my enumerated type (919). Does anyone know if there are such constraints on enumerated types? I'm using a GCC based compiler. Or, if you have any other ideas, it would be much appreciated. Thanks.
Just curiosity: what is the usefulness of such a
enum? :)If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles] -
Just curiosity: what is the usefulness of such a
enum? :)If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles] -
Hello. I'm writing some C code for an embedded application, and I've run into a problem wherein a compare against an enumerated value is not being executed correctly. Take the following code snippet, for example:
typedef unsigned int UINT16;
typedef enum enum_items_tag
{
ITEM_1,
ITEM_2,
ITEM_3,/* ... */
ITEM_918,
MAX_ENUM_ITEMS
} enum_items_t;UINT16 n;
for ( n = 0; n < MAX_ENUM_ITEMS; n++ )
{
// Do something
}The code executes as expected, until n is incremented to equal MAX_ENUM_ITEMS, at which time the compare fails, and execution continues within the loop (when it should have exited). I've done things like this in the past without any problems. I've tried re-typing n as enum_items_t (i.e. declaring n as "enum_items_t n"), as well as type casting MAX_ENUM_ITEMS as UINT16. The only other thing I can think of at this point is that maybe there is an issue with the number of items there are in my enumerated type (919). Does anyone know if there are such constraints on enumerated types? I'm using a GCC based compiler. Or, if you have any other ideas, it would be much appreciated. Thanks.
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It's used for quickly indexing into an array, rather than having to use processor time to search for an element.
Well, I cannot see any speed advantage. Would you please elaborate a bit? :)
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]