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object01
Joined: 13 May 2004
Posts: 90
Location: Nashville, TN
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| sizeof not operating correctly on array member of struct |
 Posted: Mon Oct 11, 2004 3:29 pm |
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I have a structure defined as follows:
| Code: | struct STRUCT_INFO {
U32_2xU16_4xU8 sssSize;
char GUID[16];
U16_2xU8 numberOfConfigurations;
unsigned int8 numberOfAudioChunks;
unsigned int32 configurationAddresses[MAX_CONFIGURATIONS];
unsigned int16 numberOfTuples;
}; |
I also have a function that looks like this:
| Code: | void f(struct STRUCT_INFO *structPtr) {
unsigned int8 sizeVar;
sizeVar = sizeof(structPtr->GUID);
} |
I would expect sizeVar to be set to 16, since the member array is statically allocated. But it gets 2 instead. Am I missing a syntax gotcha?
--
Jeff S. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Oct 11, 2004 3:46 pm |
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Can you post a full test program, in which you call the function,
and define all those special data types ?
I did a test program, and it appeared to work OK (from looking
at the .LST file), but unless we see your test program,
we're not really looking at the same problem. |
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object01
Joined: 13 May 2004
Posts: 90
Location: Nashville, TN
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| Posted: Mon Oct 11, 2004 3:50 pm |
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| PCM programmer wrote: | Can you post a full test program, in which you call the function,
and define all those special data types ?
I did a test program, and it appeared to work OK (from looking
at the .LST file), but unless we see your test program,
we're not really looking at the same problem. |
I'll have to extract the relevant pieces, 'cause I'm prohibiting from posting it as-is.
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Jeff S. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Oct 11, 2004 4:03 pm |
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I didn't mean post your whole program. I meant just re-post
the parts that were in your original post, plus put in one line
of code to call the function. ie., put in a main().
And if necessary, get rid of the fancy custom data types and
put in a basic type, which is what I suspect they are anyway.
In other words, you don't have to give away any IP, just
make us a test program so that we can compile it and look
at the .LST file. |
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object01
Joined: 13 May 2004
Posts: 90
Location: Nashville, TN
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| Posted: Mon Oct 11, 2004 4:13 pm |
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| PCM programmer wrote: | I didn't mean post your whole program. I meant just re-post
the parts that were in your original post, plus put in one line
of code to call the function. ie., put in a main().
And if necessary, get rid of the fancy custom data types and
put in a basic type, which is what I suspect they are anyway.
In other words, you don't have to give away any IP, just
make us a test program so that we can compile it and look
at the .LST file. |
Here's a standalone source file that demonstrates the problem. I'm using PCH v3.212 with a PIC18F452. For all I know my fancy typing may be contributing to the problem, so I've left it in.
| Code: | #include "18F452.h" // Select the target processor
#device *=16
#id checksum // The ID locations in the PIC will be the firmware checksum
// Fuses are really just suggested settings for the PIC programmer
#fuses HS,NOWDT,PUT,NOPROTECT,BROWNOUT,NOLVP,NOCPD,NOWRT
#use delay (clock=24000000) // Instruct the compiler to generate delay routines based on a 24MHz clock (NO WDT REPORTING)
#define SSS_MAX_CONFIGURATIONS 2
struct STRUCT_SSS_INFO {
char GUID[16];
unsigned int8 numberOfConfigurations;
unsigned int8 numberOfAudioChunks;
unsigned int32 configurationAddresses[SSS_MAX_CONFIGURATIONS];
unsigned int16 numberOfEpochTuples;
};
enum SSS_STATUS {SSS_OK, SSS_TIMEOUT, SSS_AUDIO_PIC_NOT_RESPONDING};
SSS_STATUS sss__readSSS(struct STRUCT_SSS_INFO *sssInfoPtr) {
unsigned int8 sizeVar;
sizeVar = sizeof(sssInfoPtr->GUID);
}
void main() {
struct STRUCT_SSS_INFO structVar;
sss__readSSS(&structVar);
} |
--
Jeff S. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Oct 11, 2004 4:27 pm |
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I don't have PCH in vs. 3.212, so I tested it with PCM.
Results:
PCM 3.212 has the error:
| Code: | 0000 00307 ..... sizeVar = sizeof(sssInfoPtr->GUID);
0004 3002 00308 MOVLW 02
0005 00BF 00309 MOVWF 3F |
PCM 3.191 has the error:
| Code: | 0000 00290 ..... sizeVar = sizeof(sssInfoPtr->GUID);
0004 3002 00291 MOVLW 02
0005 00BF 00292 MOVWF 3F |
PCM 3.188 works:
| Code: | 0000 00290 ..... sizeVar = sizeof(sssInfoPtr->GUID);
0004 3010 00291 MOVLW 10
0005 00BF 00292 MOVWF 3F |
---------------
As a side note, this is why people are always wishing that CCS
would do regression testing to prevent this kind of thing.
http://www.webopedia.com/TERM/R/regression_testing.html
http://c2.com/cgi/wiki?RegressionTesting |
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