Alternate screen buffer in Xterm/FreeBSD

[Bertram Scharpf]

Hi,

this is difficult to google for. I remember the old Linux times when
it worked but it doesn't in FreeBSD.

In a terminal window I oftenly pipe some progams output to vim:

$ someprg | vim -

When the program fails and outputs an error message to stderr the
terminals contents will be overwritten by Vim.

I know from some old Linux installations that Less and Vim are able to
switch to an alternate screen buffer. They use the escape sequences
"\e[?1049h" and "\e[?1049l" to switch back respectively.

Probably I have to recompile some library. Where is the switch to
activate it in FreeBSD?

Thanks in advance.

Bertram

--
Bertram Scharpf
Stuttgart, Deutschland/Germany
http://www.bertram-scharpf.de

[Ben Schmidt]

Bertram Scharpf wrote:
> Hi,
>
> this is difficult to google for. I remember the old Linux times when
> it worked but it doesn't in FreeBSD.
>
> In a terminal window I oftenly pipe some progams output to vim:
>
> $ someprg | vim -
>
> When the program fails and outputs an error message to stderr the
> terminals contents will be overwritten by Vim.
>
> I know from some old Linux installations that Less and Vim are able to
> switch to an alternate screen buffer. They use the escape sequences
> "\e[?1049h" and "\e[?1049l" to switch back respectively.
>
> Probably I have to recompile some library. Where is the switch to
> activate it in FreeBSD?
>
> Thanks in advance.
>
> Bertram

I thought this usually 'just worked'. But check :help xterm-save-screen
perhaps. It mentions a Vim feature that needs to be compiled in, so
maybe that is missing. Else it mentions the Vim termcap options to set,
for turning the feature off, and I suppose you could use the reverse
idea to turn it on.

Cheers,

Ben.

[Bram Moolenaar]

Bertram Scharpf wrote:

> this is difficult to google for. I remember the old Linux times when
> it worked but it doesn't in FreeBSD.
>
> In a terminal window I oftenly pipe some progams output to vim:
>
> $ someprg | vim -
>
> When the program fails and outputs an error message to stderr the
> terminals contents will be overwritten by Vim.
>
> I know from some old Linux installations that Less and Vim are able to
> switch to an alternate screen buffer. They use the escape sequences
> "\e[?1049h" and "\e[?1049l" to switch back respectively.
>
> Probably I have to recompile some library. Where is the switch to
> activate it in FreeBSD?

No need to recompile. You just need to change your termcap to set the
"ti" and "te" entries. Here is a hint:

:ti=\E7\E[r\E[?47h:te=\E[?47l\E8:

--
Shit makes the flowers grow and that's beautiful

/// Bram Moolenaar -- Br...@Moolenaar.net -- http://www.Moolenaar.net \\\
/// sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
\\\ download, build and distribute -- http://www.A-A-P.org ///
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[Bertram Scharpf]

Hi Ben,

Am Samstag, 26. Jul 2008, 21:30:35 +1000 schrieb Ben Schmidt:

>
> Bertram Scharpf wrote:
> > I know from some old Linux installations that Less and Vim are able to
> > switch to an alternate screen buffer. They use the escape sequences

> > "\e[?1047h" and "\e[?1047l" to switch back respectively.

> >
> > Probably I have to recompile some library. Where is the switch to
> > activate it in FreeBSD?
>

> I thought this usually 'just worked'. But check :help xterm-save-screen
> perhaps. It mentions a Vim feature that needs to be compiled in, so
> maybe that is missing. Else it mentions the Vim termcap options to set,
> for turning the feature off, and I suppose you could use the reverse
> idea to turn it on.

The help topic describes it exactly and I solved it.

Much thanks!

[Tony Mechelynck]

IIUC, that's the +xterm_save feature. It is never enabled by default,
not even in huge builds with +x11. To enable it, uncomment the #define
FEAT_XTERM_SAVE at (or near) line 831 of src/feature.h, then delete
src/auto/config.cache if it exists, and use "make reconfig 2>&1 |tee
makecfg.log" to reconfigure and recompile (after making sure your
configure arguments are set up in their respective environment
variables, see
http://users.skynet.be/antoine.mechelynck/vim/compunix.htm#p1 ). Then,
of course, if the configure, compilation & link look all right, install
the result with "make install".

I have set this feature, and in konsole ('term'=xterm) I see
t_ti=^[7^[[?47h
t_te=^[[2J^[?47l^[8

In the GUI ('term'=builtin_gui) and the linux console ('term'=linux)
they are unset.

Best regards,
Tony.
--
Fakir, n:
A psychologist whose charismatic data have inspired almost
religious devotion in his followers, even though the sources seem to
have shinnied up a rope and vanished.

[Bertram Scharpf]

Hi,

Am Dienstag, 29. Jul 2008, 19:51:12 +0200 schrieb Tony Mechelynck:
>
> On 26/07/08 13:30, Ben Schmidt wrote:
> > Bertram Scharpf wrote:
> IIUC, that's the +xterm_save feature. It is never enabled by default,
> not even in huge builds with +x11.

Indeed, a :version call reveals that the feature is not enabled here.
Anyway, the termcap trimming helped!?!?

> I have set this feature, and in konsole ('term'=xterm) I see
> t_ti=^[7^[[?47h
> t_te=^[[2J^[?47l^[8

As Tom Dickey already mentioned, \e[?1049 better reflects the combined
save-cursor, clear-screen and change-to-alternate operations.