Simple question: Can scanf read/accept a "small integer" into an unsigned char in ANSI C?
example code un_char.c:
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
unsigned char character;
scanf("%hhu", &character);
return EXIT_SUCCESS;
}
Compiled as:
$ gcc -Wall -ansi -pedantic -o un_char un_char.c
un_char.c: In function ‘main’:
un_char.c:8: warning: ISO C90 does not support the ‘hh’ gnu_scanf length modifier
hh
isn't supported by ISO C90. So what scanf conversion can be used in this situation?
Jonathan Leffler
No: C89 (C90) does not support '%hhu'
to read a string of digits into an unsigned char. That is a feature in C99.
You would have to read into an unsigned integer ('%u'
) or unsigned short ('%hu'
) and then check that the result is with the range of an unsigned char.
Read it into an unsigned short/int and do some range checking after if you need to.
来源:https://stackoverflow.com/questions/2231056/ansi-c-iso-c90-can-scanf-read-accept-an-unsigned-char