奇怪的getch + kbhit行为 [英] strange getch+kbhit behaviour

问题描述

在下面的代码中发生了一些奇怪的事情！如果我按下任何

的ALT +箭头键，它们会从缓冲区中提取两次然后getch

似乎停止了;如果我发布并再次按下ALT +箭头没有任何变化：

退出这个条件的唯一方法是按下另一个键一个

时间。

似乎发生的事情是kbhit说缓冲区中存在一些密钥

但是getch看不到任何数据并且等待密钥。为什么会这样？

如果我删除延迟，一切正常。我已经插入一个延迟

来重现我在另一个更大的项目中发现的问题

其中循环延迟是155ms。

最后一件事：我已经在新主板上验证了这个问题！


请帮助我!!

谢谢。

西蒙娜

#include< stdio.h>

#include< dpmi.h>


int句柄（ ）

{

int vv;


int lo，hi;


__dpmi_regs reg;


reg.x.ax = 0x10<< 8; / *将10h移入AH * /

__dpmi_int（0x16，& reg）;


vv = reg.x.ax;

lo = vv& 0X00FF;

hi =（vv& 0XFF00）> 8;

vv =（（（= = 0）|（lo == 224））？hi +256：lo）;


返回vv;


} //句柄

int main（void）

{

int i;


do

{

i = 0;

while（kbhit（））

{

fprintf（stdout，" i =％d \ n"，i ++ ）;

fprintf（stdout，"％c\ n"，getch（））;

}


fprintf （stdout，"％d \ nn"，Handle（））;

延迟（155）;


} while（1）;

}

In the following code something strange happens ! If I keep pressed any
of ALT+Arrow, keys, they are extracted two times from buffer then getch
seems to stop; if I release and press again ALT+arrow nothing changes:
the only way to exit from this condition is press another key a single
time.
What seems to happen is that kbhit say some keys are present in buffer
but for getch don''t see any data and waits for a key. Why this happen ?
If I remove the delay all is working correctly. I''ve inserted a delay
to reproduce thi problem that I''ve found on another bigger project
where loop delay is 155ms.
Last thing: I''ve verified this problem only on newer motherboards !

Please help me !!
Thank you.
Simone
#include <stdio.h>
#include <dpmi.h>

int Handle()
{
int vv;

int lo, hi;

__dpmi_regs reg;

reg.x.ax = 0x10 << 8; /* shift 10h into AH */
__dpmi_int( 0x16, &reg);

vv= reg.x.ax ;
lo = vv & 0X00FF;
hi= ( vv & 0XFF00) >8;
vv=( ((lo == 0)|(lo == 224)) ? hi+256 : lo);

return vv;

} // Handle
int main(void)
{
int i;

do
{
i=0;
while(kbhit())
{
fprintf(stdout,"i=%d\n",i++);
fprintf(stdout,"%c\n",getch());
}

fprintf(stdout,"%d\n",Handle());
delay(155);

} while(1);
}

推荐答案

simnav写道：

simnav wrote:

在下面代码奇怪的发生了！如果我按下任何

的ALT +箭头键，它们会从缓冲区中提取两次然后getch

似乎停止了;如果我发布并再次按下ALT +箭头没有任何变化：

退出这个条件的唯一方法是按下另一个键一个

时间。

似乎发生的事情是kbhit说缓冲区中存在一些密钥

但是getch看不到任何数据并且等待密钥。为什么会这样？

如果我删除延迟，一切正常。我已经插入一个延迟

来重现我在另一个更大的项目中发现的问题

其中循环延迟是155ms。

最后一件事：我已经在新主板上验证了这个问题！


请帮助我!!

谢谢。

Simone


#include< stdio.h>

#include< dpmi.h>


int句柄（）

{

int vv;


int lo，hi;


__dpmi_regs reg;


reg.x.ax = 0x10<< 8; / *将10h移入AH * /

__dpmi_int（0x16，& reg）;


vv = reg.x.ax;

lo = vv& 0X00FF;

hi =（vv& 0XFF00）> 8;

vv =（（（= = 0）|（lo == 224））？hi +256：lo）;


返回vv;


} //句柄


int main（无效）

{

int i;


do

{

i = 0;

while（kbhit（））

{

fprintf（stdout，" i =％d \ n"，i ++）;

fprintf（stdout，"％c\ n"，getch（））;

}


fprintf（stdout，"％d \ n"，Handle（））;

延迟（155）;


} while（1 ）;

}

In the following code something strange happens ! If I keep pressed any
of ALT+Arrow, keys, they are extracted two times from buffer then getch
seems to stop; if I release and press again ALT+arrow nothing changes:
the only way to exit from this condition is press another key a single
time.
What seems to happen is that kbhit say some keys are present in buffer
but for getch don''t see any data and waits for a key. Why this happen ?
If I remove the delay all is working correctly. I''ve inserted a delay
to reproduce thi problem that I''ve found on another bigger project
where loop delay is 155ms.
Last thing: I''ve verified this problem only on newer motherboards !

Please help me !!
Thank you.
Simone
#include <stdio.h>
#include <dpmi.h>

int Handle()
{
int vv;

int lo, hi;

__dpmi_regs reg;

reg.x.ax = 0x10 << 8; /* shift 10h into AH */
__dpmi_int( 0x16, &reg);

vv= reg.x.ax ;
lo = vv & 0X00FF;
hi= ( vv & 0XFF00) >8;
vv=( ((lo == 0)|(lo == 224)) ? hi+256 : lo);

return vv;

} // Handle
int main(void)
{
int i;

do
{
i=0;
while(kbhit())
{
fprintf(stdout,"i=%d\n",i++);
fprintf(stdout,"%c\n",getch());
}

fprintf(stdout,"%d\n",Handle());
delay(155);

} while(1);
}

getch（）可能需要一个ASCII字符，而不仅仅是一些

键盘键

getch() probably expects an ASCII character, not just some
keyboard key

jacob navia说：

jacob navia said:

simnav写道：

simnav wrote:

< snip>

<snip>

>似乎发生的事情是kbhit说缓冲区中存在一些键
但是对于getch don''看到任何数据并等待密钥。为什么会这样？

>What seems to happen is that kbhit say some keys are present in buffer
but for getch don''t see any data and waits for a key. Why this happen ?

< snip>

<snip>

>

getch（）可能需要一个ASCII字符，而不仅仅是一些

键盘键

>
getch() probably expects an ASCII character, not just some
keyboard key

这个错误的答案就是一个很好的例子，说明为什么你应该在一个致力于相应的新闻组上询问

特定于平台的问题

平台。


-

Richard Heathfield

Usenet是一个奇怪的地方 - dmr 29/7/1999
http://www.cpax.org.uk

电子邮件：rjh在上面的域名（但显然放弃了www）

That incorrect answer is a great example of why you should ask
platform-specific questions on a newsgroup devoted to the appropriate
platform.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)

" simnav" < nospamtnxwrites：

"simnav" <nospamtnxwrites:

在下面的代码中发生了一些奇怪的事情！如果我按下任何

的ALT +箭头键，它们会从缓冲区中提取两次然后getch

似乎停止了;如果我发布并再次按下ALT +箭头没有任何变化：

退出此条件的唯一方法是按下另一个键一个

时间。

In the following code something strange happens ! If I keep pressed any
of ALT+Arrow, keys, they are extracted two times from buffer then getch
seems to stop; if I release and press again ALT+arrow nothing changes:
the only way to exit from this condition is press another key a single
time.

你的文章在你发布它的前三次是偏离主题的。

它仍然是偏离主题的。请把它带到讨论

getch和kbhit的小组。我怀疑你想要一个MS-DOS编程

新闻组。

-

你称之为* C *问题？你到底在吸什么？ --Kaz

Your article was off-topic the first three times you posted it.
It is still off-topic. Please take it to a group that discusses
getch and kbhit. I suspect you want an MS-DOS programming
newsgroup.
--
"You call this a *C* question? What the hell are you smoking?" --Kaz

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