《MISRA QAC2012》 8.5 Required Rule-5.6

8.5  Required Rule-5.6

A typedef name shall be a unique identifier

Amplification

A typedef name shall be unique across all name spaces and translation units. Multiple declarations of the same typedef name are only permitted by this rule if the type definition is made in a header file and that header file is included in multiple source files.

Exception

The typedef name may be the same as the structure, union or enumeration tag name associated with the typedef.

Implemented by QAC messages:

1506	The identifier '%1s' is declared as a typedef and is used elsewhere for a different kind of declaration.
1507	'%1s' is used as a typedef for different types.
1508	The typedef '%1s' is declared in more than one location.
3448	Declaration of typedef '%s' is not in a header file although it is used in a definition or declaration with external linkage.

Typedef 应该定义在头文件里，被其他文件引用时，使用#include包含这个头文件

如果用Typedef 定义的变量声明具有外部链接属性的变量或者函数，应该把Typedef 放在头文件

/*PRQA S 2017 ++*/

typedef int TYPE;         /* Message 3448 */
extern TYPE foo(void);    /* Message 3447 */ 

extern TYPE foo(void)
{
    return 1;
}