system("cls") to slow

[Chad Gorshing]

When I use 'system("cls")' there is a delay about a second's worth. In DOS
when I type cls, there is no delay.

What gives?

[Luis Abreu]

If you're using VC++ ( win32 console application ) then you can always use
the console functions to clean the screen. there's a sample about it in msdn.microsoft.com

[never worked]

"Luis Abreu" <luisabreu@netmadeira> wrote:
>
>If you're using VC++ ( win32 console application ) then you can always use
>the console functions to clean the screen. there's a sample about it in
msdn.microsoft.com

I've never gotten this function to work.
I've see many respones directing people here,
but have they tried this function themselves??
Has anyone gotten this thing to work properly?

[Jason]

"never worked" <neverworked@never> wrote:
>
>"Luis Abreu" <luisabreu@netmadeira> wrote:
>>
>>If you're using VC++ ( win32 console application ) then you can always
use
>>the console functions to clean the screen. there's a sample about it in
>msdn.microsoft.com
>
>I've never gotten this function to work.
>I've see many respones directing people here,
>but have they tried this function themselves??
>Has anyone gotten this thing to work properly?


Yes, Use the GNU g++ compiler. It works fine with that. VC++ is terrible
with system calls. Try searching for DJGPP or cygwin for WIN32 GNU tools.

[Nick G-B]

"Jason" <kahuna01@hotmail.com> wrote:
>
>"never worked" <neverworked@never> wrote:
>>
>>"Luis Abreu" <luisabreu@netmadeira> wrote:
>>>
>>>If you're using VC++ ( win32 console application ) then you can always
>use
>>>the console functions to clean the screen. there's a sample about it in
>>msdn.microsoft.com
>>
>>I've never gotten this function to work.
>>I've see many respones directing people here,
>>but have they tried this function themselves??
>>Has anyone gotten this thing to work properly?
>
>
>Yes, Use the GNU g++ compiler. It works fine with that. VC++ is terrible
>with system calls. Try searching for DJGPP or cygwin for WIN32 GNU tools.
>
Oh come on, just use that trusty asm{} block! :) Gets rid of timing delays,
and household pets if you're not careful...

[Jason]

"Nick G-B" <nickgb@antisocial.com> wrote:
>
>"Jason" <kahuna01@hotmail.com> wrote:
>>
>>"never worked" <neverworked@never> wrote:
>>>
>>>"Luis Abreu" <luisabreu@netmadeira> wrote:
>>>>
>>>>If you're using VC++ ( win32 console application ) then you can always
>>use
>>>>the console functions to clean the screen. there's a sample about it
in
>>>msdn.microsoft.com
>>>
>>>I've never gotten this function to work.
>>>I've see many respones directing people here,
>>>but have they tried this function themselves??
>>>Has anyone gotten this thing to work properly?
>>
>>
>>Yes, Use the GNU g++ compiler. It works fine with that. VC++ is terrible
>>with system calls. Try searching for DJGPP or cygwin for WIN32 GNU tools.
>>
>Oh come on, just use that trusty asm{} block! :) Gets rid of timing delays,
>and household pets if you're not careful...

[Jason]

One more Idea that pops into my head is to make your own screenclear function.
I was reading Danny Kalev's post about multiple lines and got an idea (i
dont know if its been used before).

int ScreenClear(const int ScreenRows)
{
if (ScreenRows < 0 || ScreenRows > MAXROWS) {
cerr << "The Screen Does not support this number
of rows.";

return 1;
}

for(int i = ScreenRows; i > 0; --i) cout << '\n';

return 0;
}

This function depends on MAXROWS being defined somewhere in the scope of
the function. MAXROWS will depend on the size of your Console, Xterm, or
DOS window.
If anyone has even more ideas please post a reply.

best wishes,
Jason

[Nickolaus]

This is a great idea and all, but how does it's speed compare to that of system(
"cls" )? Condsidering it has to collect values for ScreenRows and MAXROWS.


-Nickolaus


"Jason" <kahuna01@hotmail.com> wrote:
>
>One more Idea that pops into my head is to make your own screenclear function.
>I was reading Danny Kalev's post about multiple lines and got an idea (i
>dont know if its been used before).
>
>int ScreenClear(const int ScreenRows)
>{
> if (ScreenRows < 0 || ScreenRows > MAXROWS) {
> cerr << "The Screen Does not support this number
> of rows.";
>
> return 1;
> }
>
> for(int i = ScreenRows; i > 0; --i) cout << '\n';
>
> return 0;
>}
>
>This function depends on MAXROWS being defined somewhere in the scope of
>the function. MAXROWS will depend on the size of your Console, Xterm, or
>DOS window.
>If anyone has even more ideas please post a reply.
>
>best wishes,
>Jason
>

[Jason]

"Nickolaus" <watts.77@osu.edu> wrote:
>
>This is a great idea and all, but how does it's speed compare to that of
system(
>"cls" )? Condsidering it has to collect values for ScreenRows and MAXROWS.
>
>
>-Nickolaus
>

With The GNU C++ compiler, the speed will be slightly slower using the function,
but with Visual C++ (the compiler that was being used with the original question)
the function is much, much faster. Ive never tried the ASM code block that
some people recommend for VC++, but I imagine that its faster than system("cls");
also.

Jason

[Justin Arruda]

This probably won't answer any questions, but I hope to get this answered.
I must have missed something, but what even happened to clrscr(); in C.
I remember using it all the time and it was fast for me. Can someone tell
me why is was all of a sudden upsupported?

"Jason" <kahuna01@hotmail.com> wrote:
>
>"Nickolaus" <watts.77@osu.edu> wrote:
>>
>>This is a great idea and all, but how does it's speed compare to that of
>system(
>>"cls" )? Condsidering it has to collect values for ScreenRows and MAXROWS.
>>
>>
>>-Nickolaus
>>
>
>With The GNU C++ compiler, the speed will be slightly slower using the function,
>but with Visual C++ (the compiler that was being used with the original
question)
>the function is much, much faster. Ive never tried the ASM code block that
>some people recommend for VC++, but I imagine that its faster than system("cls");
>also.
>
>Jason
>

[time travle2018]

It's been 18 years .


I found the answer on this website.


http://www.cplusplus.com/forum/beginner/100115/

Answered by JLBorges:

> I'm getting an explosion of syntax errors as soon as I #include windows.h.

There are name clashes with macros defined in <windows.h>

So, insulate the windows stuff in a separate component:

Header cls.h




#ifndef CLS_H_INCLUDED
#define CLS_H_INCLUDED

void cls() ;

#endif // CLS_H_INCLUDED




Implementation cls.cc



#include "cls.h"
#include <windows.h>

void cls()
{
HANDLE console = ::GetStdHandle(STD_OUTPUT_HANDLE) ;
CONSOLE_SCREEN_BUFFER_INFO csbi;
::GetConsoleScreenBufferInfo( console, &csbi );
COORD origin = { 0, 0 } ;
DWORD written ;
::FillConsoleOutputCharacterA( console, ' ' , csbi.dwSize.X * csbi.dwSize.Y,
origin, &written );
::FillConsoleOutputAttribute( console, csbi.wAttributes, csbi.dwSize.X * csbi.dwSize.Y,
origin, &written );
::SetConsoleCursorPosition( console, origin );
}




And then #include "cls.h" in those translation units where you want to call cls();

[2kaud]

[When posting code, please use code tags so that the code is readable. Either include the tags at the start and end of the code or Go Advanced, select the formatted code and click '#'.]

system("cls") is slightly slower than using cls at dos prompt as system() first creates a new process which executes the supplied command.

clrscr() originated from Borland turbo c/c++. It was defined in conio.h and is non-standard. Whether clrscr() is supported by a particular compiler depends upon the compiler - it is implementation specific. It is not supported by Microsoft VS.