arning: passing argument from incompatible pointer type
Guest
#1171916
I'm getting this error from WinARM:
Warning: passing argument 4 of 'AT91F_TWI_ReadByte' from incompatible
pointer type
with this code:
char read[5];
int AT91F_TWI_ReadByte(const AT91PS_TWI pTwi ,int mode, /
int int_address, char * data, int nb)
{
some code here;
}
void main(void)
{
AT91F_TWI_ReadByte(AT91C_BASE_TWI, LED_CONTROLLER0, 0x02, &read, 1);
}
What is incompatible with the pointer?
- Joe
Guest
#1171917
1. Mistake in code, no reason to blame WinARM 2. warning != error 3. test with &read[0] or just read and try to understand the difference to &read 4. use int main(void) to avoid another warning 5. read a C-book (i.e. Brian W. Kernighan and Dennis M. Ritchie, The C Programming Language) or C-tutorial soon. &read has type char** not char* you simply need just read on its own which has type char[] which is compatible with char*, or &read[0] which is a char*. A char[] when passed as a function parameter always degrades to char* in any case. The only difference between a char* and char[] is the value of sizeof(); char read[10] ; char* pRead = read ; sizeof(read) == 10 sizeof(pRead) == 4 (on a 32bit architecture such as ARM) Clifford
Guest
#1171919
Clifford Slocombe wrote: > &read has type char** not char* you simply need just read on its own > which has type char[] which is compatible with char*, or &read[0] which > is a char*. Thanks Clifford. The code is a sample from Atmel, so evidently they don't know what they are doing either. (By the way, the IAR compiler doesn't issue any warnings in it's default setup.) And Martin, I was in no way blaming WinArm! I love WinARM! I appologise for calling the warning an error. - Joe Reply |