vs2015无法解析外部符号__imp__fprintf 以及imp_iob_func错误

使用vs2015编译ffmpeg的一个程序时，出现了__imp__fprintf和__imp____iob_func 的错误，以下是官方的回答：

In visual studio 2015, stdin, stderr, stdout are defined as follow :

#define stdin  (__acrt_iob_func(0))
#define stdout (__acrt_iob_func(1))
#define stderr (__acrt_iob_func(2))

But previously, they were defined as:

#define stdin  (&__iob_func()[0])
#define stdout (&__iob_func()[1])
#define stderr (&__iob_func()[2])

So now __iob_func is not defined anymore which leads to a link error when using a .lib file compiled with previous versions of visual studio.

To solve the issue, you can try defining __iob_func() yourself which should return an array containing {*stdin,*stdout,*stderr}.

Regarding the other link errors about stdio functions (in my case it was sprintf()), you can add legacy_stdio_definitions.lib to your linker options.

可以看出，stdin, stderr, stdout 三个函数在vs2015中和以前的vs版本的定义不同，所以报错。__imp____iob_func 解决方法：

使用{*stdin,*stdout,*stderr}数组自己定义__iob_func()，如下写法：

extern "C" { FILE __iob_func[3] = {*stdin,*stdout,*stderr }; }

对于__imp__fprintf的解决方法：

#pragma comment(lib, "legacy_stdio_definitions.lib")