Testit(1, NULL) // 2nd problem: NULL is not a char* Testit(0, 0xFFFFFFFF) // 1st problem: 0xffffffff is not an int When they are compiled by using /clr (Common Language Runtime Compilation), programs that use these macros may generate unexpected results because of differences between native and common language runtime (CLR) type systems.
In all other cases, use the macros in STDARGS.H.
VA LIST IAR C CODE
The macros in VARARGS.H are deprecated and are retained only for backwards compatibility with code that was written before the ANSI C89 standard. va_end must be called on each argument list that's initialized with va_start or va_copy before the function returns. The next argument that's retrieved by va_arg from dest is the same as the next argument that's retrieved from src.Īfter all arguments have been retrieved, va_end resets the pointer to NULL. The src parameter must already be initialized with va_start it may have been updated with va_arg calls, but must not have been reset with va_end. Va_copy makes a copy of a list of arguments in its current state. va_arg can be used any number of times in the function to retrieve arguments from the list. Va_arg retrieves a value of type from the location that's given by arg_ptr, and increments arg_ptr to point to the next argument in the list by using the size of type to determine where the next argument starts. va_start must be used before va_arg is used for the first time. If prev_param is declared with the register storage class, the macro's behavior is undefined. The argument prev_param is the name of the required parameter that immediately precedes the first optional argument in the argument list. The argument arg_ptr must have the va_list type. Va_start sets arg_ptr to the first optional argument in the list of arguments that's passed to the function.
The C standard macros, defined in STDARG.H, are used as follows: The optional arguments are accessed through the macros in STDARG.H (or VARARGS.H for code that was written before the ANSI C89 standard), which sets a pointer to the first optional argument in the argument list, retrieves arguments from the list, and resets the pointer when argument processing is completed. The required arguments are declared as ordinary parameters to the function and can be accessed through the parameter names. These macros assume that the function takes a fixed number of required arguments, followed by a variable number of optional arguments.
VA LIST IAR C ISO
There are two versions of the macros: The macros defined in STDARG.H conform to the ISO C99 standard the macros defined in VARARGS.H are deprecated but are retained for backward compatibility with code that was written before the ANSI C89 standard.
VA LIST IAR C PORTABLE
The va_arg, va_copy, va_end, and va_start macros provide a portable way to access the arguments to a function when the function takes a variable number of arguments. va_copy, va_start and va_end do not return values. Parameter that precedes the first optional argument. Pointer to the initialized list of arguments to copy to dest. Pointer to the list of arguments to be initialized from src ) // (deprecated Pre-ANSI C89 standardization version)
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