#include <stdio.h>
typedef int f(int, ...);
int main()
{
printf("%d,%d", sizeof(printf), sizeof(f));
return 0;
}
结果为1,1,见http://codepad.org/fg0r4NhG
解决方案：8分
解决方案：8分
参考gcc或g++中sizeof的实现。
解决方案：8分
$ cat test.c
#include <stdio.h>
typedef int f(int, ...);
int main()
{
printf("%d,%d", sizeof(printf), sizeof(f));
return 0;
}
$ gcc --std=c11 --pedantic-errors test.c
test.c: In function ‘main’:
test.c:5:27: error: invalid application of ‘sizeof’ to a function type [-Wpointer-arith]
printf("%d,%d", sizeof(printf), sizeof(f));
^
test.c:5:44: error: invalid application of ‘sizeof’ to a function type [-Wpointer-arith]
printf("%d,%d", sizeof(printf), sizeof(f));
^
test.c:5:5: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘long unsigned int’ [-Wformat=]
printf("%d,%d", sizeof(printf), sizeof(f));
^
test.c:5:5: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘long unsigned int’ [-Wformat=]
$ gcc --version
gcc (Ubuntu 4.9.2-10ubuntu13) 4.9.2
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
解决方案：8分
ISO/IEC 9899:1999 (E) ©ISO/IEC
6.5.3.4 The sizeof operator
Constraints
1 The sizeof operator shall not be applied to an expression that has function type or an
incomplete type, to the parenthesized name of such a type, or to an expression that
designates a bit-field member.
C89 (ISO/IEC 9899:1990)本人从来没有见过，非常抱歉。
但是从 http://en.cppreference.com/w/c/language/sizeof 的叙述来看，sizeof 的这一要求从 C89 以来没有发生变化。这个网站对在某版标准开始发生变化的内容都有特别的标注。
6.5.3.4 The sizeof operator
Constraints
1 The sizeof operator shall not be applied to an expression that has function type or an
incomplete type, to the parenthesized name of such a type, or to an expression that
designates a bit-field member.
C89 (ISO/IEC 9899:1990)本人从来没有见过，非常抱歉。
但是从 http://en.cppreference.com/w/c/language/sizeof 的叙述来看，sizeof 的这一要求从 C89 以来没有发生变化。这个网站对在某版标准开始发生变化的内容都有特别的标注。
解决方案：8分
学会使用百度和grep
解决方案：48分
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