scanf函数返回什么？

scanf 在以下情况下返回的值是多少：

int g;
int p = scanf("%d", &g);      // Originally: int p = scanf("%d", g);

我知道签名scanf函数是：

int scanf(const char *format, ...)

是什么int该函数返回的值？

来自man page:

NAME
       scanf,  fscanf, sscanf, vscanf, vsscanf, vfscanf 

       ...

RETURN VALUE
       These functions return the number of input items  successfully  matched
       and assigned, which can be fewer than provided for, or even zero in the
       event of an early matching failure.

       The value EOF is returned if the end of input is reached before  either
       the  first  successful conversion or a matching failure occurs.  EOF is
       also returned if a read error occurs, in which case the error indicator
       for  the  stream  (see ferror(3)) is set, and errno is set indicate the
       error.

就你而言，scanf()可以返回0, 1 or EOF.