__isoc99_scanf and scanf

Question

I was studying various compiler option in GCC and observing changes when I made changes in the standard to be used.

$ gcc Q1.c -Wall -save-temps -o Q1
$ vi Q1.s
         


        

Answer 1

scanf(3) manual mentions several type modifiers characters introduced in c99:

j      As for h, but the next pointer is a pointer to an intmax_t or a uintmax_t.  This modifier was introduced in C99
t      As for h, but the next pointer is a pointer to a ptrdiff_t.  This modifier was introduced in C99.
z      As for h, but the next pointer is a pointer to a size_t.  This modifier was introduced in C99.
a      (C99) Equivalent to f