MISRA C:2025 Rule 17.12

R2026b

A function identifier should only be used with either a preceding &, or with a parenthesized parameter list

Since R2026b

Description

A function identifier should only be used with either a preceding &, or with a parenthesized parameter list ¹ .

Rationale

Using a function identifier without a preceding & or a following parenthesized parameter list is confusing. It is not clear whether the intent is to call a function or to obtain the address of the function.

Polyspace Implementation

This rule checker reports a violation if a function identifier is used without either of these:

A preceding &
A following parenthesized parameter list

Troubleshooting

If you expect a rule violation but do not see it, refer to Diagnose Why Coding Standard Violations Do Not Appear as Expected.

Examples

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Ambiguous Use of Function Identifier

In this example, the function identifier func is used without a preceding & or a following set of parenthesis. The rule checker reports violations for these ambiguous uses.

#include <stdint.h>

typedef int32_t (*func_ptr_i)(void);
extern int32_t func1(void);        /* Note: A function */
extern int32_t (*func2)(void);     /* Note: A function pointer */
void func(void)
{
	func_ptr_i pfn1 = &func1;       /*Compliant*/
	func_ptr_i pfn2 = func1;        /*Noncompliant*/
	pfn1();                    /*Compliant*/

	if(func1 == func2)         /*Noncompliant*/
	{
		/* ... */
	}
	if(func1() == func2())           /*Compliant*/
	{
		/* ... */
	}

}

Check Information

Group: Functions

Category: Advisory

AGC Category: Advisory

PQL Name: std.misra_c_2025.R17_12

Version History

Introduced in R2026b