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RENESAS TOOL NEWS on December 1, 2004: RSO-M3T-CC32R-041201D
A Note on Using
C-Compiler Package M3T-CC32R
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Please take note of the following problem in using the M3T-CC32R, the C-compiler package for the M32R family of MCUs:
- On making a function call using a pointer pointing to a function whose type has been converted by a cast operator
- Versions Concerned
M3T-CC32R V.1.00 Release 1 through V.4.30 Release 00
- Description
When a function call is made using a pointer pointing to a function
whose type has been converted by casting, the following error may
arise even if both types of each parameter and its argument match with each other:
error: type of argument does not match with prototype
- Conditions
This problem occurs if the following conditions are all satisfied:
| (1) |
The type of a pointer or integer is converted to another pointer pointing to a function by casting,
and a function call is made at the same time. |
| (2) | At least one parameter of the function to be called is array type. |
Example 1: sample1.c
-----------------------------------------------------------------------
short array[3];
void foo1(void *ptr1)
{
(*(void(*)(int, short arr[]))ptr1)(2,array);
/* Conditions (1) and (2) */
}
-----------------------------------------------------------------------
Example 2: sample2.c
-----------------------------------------------------------------------
typedef struct AAA TYPE_A;
char *ptr2;
int foo2(TYPE_A array[][3])
{
int ans;
ans = (*(int(*)(TYPE_A arr[][3]))ptr2)(array);
/* Conditions (1) and (2) */
return ans;
}
-----------------------------------------------------------------------
Example 3: sample3.c
-----------------------------------------------------------------------
typedef float TYPE_F[3];
TYPE_F array;
void foo3(void)
{
(*(void(*)(TYPE_F))0x123400)(array);
/* Conditions (1) and (2) */
}
-----------------------------------------------------------------------
- Workaround
When making a function call using a pointer pointing to a function
whose type has been converted by casting, once save the result of
casting in another pointer variable, and then make a function call using this variable.
Modification of Example 1:
-----------------------------------------------------------------------
short array[3];
void foo1(void *ptr1)
{
void (*callptr1)(int, short arr[])
/* Define a pointer variable "callptr1" */
= (void (*)(int,short arr[]))ptr1;
/* Save the cast result in "callptr1" */
(*callptr1)(2,array); /* Call a function using "callptr1" */
}
-----------------------------------------------------------------------
Modification of Example 2:
-----------------------------------------------------------------------
typedef struct AAA TYPE_A;
char *ptr2;
int foo2(TYPE_A array[][3])
{
int ans;
int (*callptr2)(TYPE_A arr[][3]);
/* Define a pointer variable "callptr2" */
callptr2 = (int(*)(TYPE_A arr[][3]))ptr2;
/* Save the cast result in "callptr2" */
ans = (*callptr2)(array); /* Call a function using "callptr2" */
return ans;
}
-----------------------------------------------------------------------
Modification of Example 3:
-----------------------------------------------------------------------
typedef float TYPE_F[3];
void *ptr3;
TYPE_F array;
void foo3(void)
{
void (*callptr3)(TYPE_F);
/* Define a pointer variable "callptr3" */
callptr3 = (void(*)(TYPE_F))0x123400;
/* Save the cast result in "callptr3" */
(*callptr3)(array); /* Call a function using "callptr3" */
}
-----------------------------------------------------------------------
- Schedule of Fixing the Problem
We plan to fix this problem in our next release of the product.
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