[GRASS5] Using 'vask' library

GRASS GRASS developer
1

Hi GRASS developers,

I have to compile a program that runs under grass using, among other things,
the 'vask' library. It compiles, but gives the following error when run:

GRASS:~ > swatgrass
'xterm-xfree86': unknown terminal type.
Error opening terminal: xterm-xfree86.
GRASS:~ >

I've determined that this message is generated when V_call() is called.
Curiously, when I run the program in gdb, it runs ok and the screen menus are
displayed just fine!

I thought maybe the problem has to do with how I linked in the termcap
library. Programmer's manual suggests using $(VASK), because "it specifies
both the UNIX curses and termcap libraries as well as $(VASKLIB)" (p. 286),
however, $(VASK) is not set when I ran 'gmake5' on the GMakefile (see below).
So I just plugged the libraries directly:
  $(CC) $(LDFLAGS) -o $@ $(LIST) -ltermcap -lcurses $(LIBES)

Below is the whole GMakefile. I'd be very glad to hear any ideas...

Thank you,

Aleksey

-------------- GMakefile --------------------------------
LIBES = $(D_LIB) $(DISPLAYLIB) $(RASTERLIB) $(GISLIB) $(VASKLIB) $(MATHLIB)
$(DATETIMELIB) $(ZLIB)

#EXTRA_CFLAGS = -DDEBUG -DBOBMGT -DLB_LUSE_SOIL -DHUMUS -DVERELMGT -DQUAL2E
-L/usr/lib

PGM = swatgrs

LIST = \
  dummy_lcra.o\
  ... more object files here ...
        main.o

./$(PGM): $(LIST) $(LIBES)
    @echo VASK = $(VASK)
    @echo VASKLIB = $(VASKLIB)
    @echo DATETIMELIB = $(DATETIMELIB)
    @echo ZLIB = $(ZLIB)
    @echo
    $(CC) $(LDFLAGS) -o $@ $(LIST) -ltermcap -lcurses $(LIBES)

$(LIBES): #

2

Aleksey Naumov wrote:

I have to compile a program that runs under grass using, among other things,
the 'vask' library. It compiles, but gives the following error when run:

GRASS:~ > swatgrass
'xterm-xfree86': unknown terminal type.
Error opening terminal: xterm-xfree86.
GRASS:~ >

This is generated by curses (or, more precisely, by the termcap or
terminfo functions which curses calls).

I've determined that this message is generated when V_call() is
called.

It's probably generated by the call to initscr() within V_init(),
although the call to system("clear") may also generate the error
(although I suspect not).

Curiously, when I run the program in gdb, it runs ok and the screen menus are
displayed just fine!

I thought maybe the problem has to do with how I linked in the termcap
library. Programmer's manual suggests using $(VASK), because "it specifies
both the UNIX curses and termcap libraries as well as $(VASKLIB)" (p. 286),
however, $(VASK) is not set when I ran 'gmake5' on the GMakefile (see below).

The documentation is incorrect; the correct invocation for linking
against the Vask library is "$(VASKLIB) $(CURSES)".

So I just plugged the libraries directly:
  $(CC) $(LDFLAGS) -o $@ $(LIST) -ltermcap -lcurses $(LIBES)

This is probably incorrect.

Most modern curses libraries use terminfo, not termcap. Also, the
terminfo functions are typically built into the curses library rather
than being a separate library.

On GNU-based systems, it's common for both libtermcap and libncurses
(libcurses.so is normally a symlink to libncurses.so) to define
symbols such as tgetent(). However, the version in libncurses will
typically use terminfo, while the version in libcurses uses termcap.

What I suspect is happening is that terminfo has a definition for
xterm-xfree86, while termcap doesn't.

I suggest using $(CURSES); that should contain the correct switch for
the curses library (either -lcurses or -lncurses), plus any necessary
dependencies (which may include termcap/terminfo libraries, and
possibly a BSD compatibility library for gtty()).

--
Glynn Clements <glynn.clements@virgin.net>

3

On Tue, Feb 12, 2002 at 12:07:10AM +0000, Glynn Clements wrote:

Aleksey Naumov wrote:

> I have to compile a program that runs under grass using, among other things,
> the 'vask' library. It compiles, but gives the following error when run:
>
> GRASS:~ > swatgrass
> 'xterm-xfree86': unknown terminal type.
> Error opening terminal: xterm-xfree86.
> GRASS:~ >

This is generated by curses (or, more precisely, by the termcap or
terminfo functions which curses calls).

> I've determined that this message is generated when V_call() is
> called.

It's probably generated by the call to initscr() within V_init(),
although the call to system("clear") may also generate the error
(although I suspect not).

> Curiously, when I run the program in gdb, it runs ok and the screen menus are
> displayed just fine!
>
> I thought maybe the problem has to do with how I linked in the termcap
> library. Programmer's manual suggests using $(VASK), because "it specifies
> both the UNIX curses and termcap libraries as well as $(VASKLIB)" (p. 286),
> however, $(VASK) is not set when I ran 'gmake5' on the GMakefile (see below).

The documentation is incorrect; the correct invocation for linking
against the Vask library is "$(VASKLIB) $(CURSES)".

Hi,

I have changed the old passage:
\textbf{Note.} The target \textit{pgm} depends on the object files \$(OBJ)
and the \textit{Vask Library} \$(VASKLIB). This is done so that
modifications to any of the \$(OBJ) files or to the \$(VASKLIB) itself will
force module reloading. However, the compile rule specifies \$(OBJ) and
\$(VASK), rather than \$(OBJ) and \$(VASKLIB). This is because \$(VASK)
specifies both the UNIX curses and termcap libraries as well as \$(VASKLIB).

to (new):

\textbf{Note.} The target \textit{pgm} depends on the object files \$(OBJ)
and the \textit{Vask Library} \$(VASKLIB). This is done so that
modifications to any of the \$(OBJ) files or to the \$(VASKLIB) itself will
force module reloading. Linking against the Vask library is \$(VASKLIB)
\$(CURSES), it specifies both the UNIX curses and termcap/terminfo libraries
as well as \$(VASKLIB).

[sorry for the Latex markup]
Does this change make sense? If not, please correct, then I publish the
updated PDF.

Thanks,

Markus

4

Markus Neteler wrote:

I have changed the old passage:

[snip]

to (new):

\textbf{Note.} The target \textit{pgm} depends on the object files \$(OBJ)
and the \textit{Vask Library} \$(VASKLIB). This is done so that
modifications to any of the \$(OBJ) files or to the \$(VASKLIB) itself will
force module reloading. Linking against the Vask library is \$(VASKLIB)
\$(CURSES), it specifies both the UNIX curses and termcap/terminfo libraries
as well as \$(VASKLIB).

[sorry for the Latex markup]
Does this change make sense? If not, please correct, then I publish the
updated PDF.

The phrase "Linking against the Vask library is \$(VASKLIB) \$(CURSES)"
isn't grammatically correct. It should probably say something like
"Linking against the Vask library is performed using \$(VASKLIB) \$(CURSES)"

Apart from that, it's OK.

--
Glynn Clements <glynn.clements@virgin.net>

5

On Tue, Feb 12, 2002 at 07:42:06AM +0000, Glynn Clements wrote:

Markus Neteler wrote:

> I have changed the old passage:

[snip]

> to (new):
>
> \textbf{Note.} The target \textit{pgm} depends on the object files \$(OBJ)
> and the \textit{Vask Library} \$(VASKLIB). This is done so that
> modifications to any of the \$(OBJ) files or to the \$(VASKLIB) itself will
> force module reloading. Linking against the Vask library is \$(VASKLIB)
> \$(CURSES), it specifies both the UNIX curses and termcap/terminfo libraries
> as well as \$(VASKLIB).
>
> [sorry for the Latex markup]
> Does this change make sense? If not, please correct, then I publish the
> updated PDF.

The phrase "Linking against the Vask library is \$(VASKLIB) \$(CURSES)"
isn't grammatically correct. It should probably say something like
"Linking against the Vask library is performed using \$(VASKLIB) \$(CURSES)"

Apart from that, it's OK.

Thanks. The updated PDF is posted on the web site.

Markus

6

Glynn, thank you for the very detailed explanation, it was right on target!
The program works ok now, once it was linked against $(CURSES).

Markus, thanks for updating the docs!

Aleksey

hit the problem right on

On Tuesday 12 February 2002 02:42, Glynn Clements wrote:

Markus Neteler wrote:
> I have changed the old passage:

[snip]

> to (new):
>
> \textbf{Note.} The target \textit{pgm} depends on the object files
> \$(OBJ) and the \textit{Vask Library} \$(VASKLIB). This is done so that
> modifications to any of the \$(OBJ) files or to the \$(VASKLIB) itself
> will force module reloading. Linking against the Vask library is
> \$(VASKLIB) \$(CURSES), it specifies both the UNIX curses and
> termcap/terminfo libraries as well as \$(VASKLIB).
>
> [sorry for the Latex markup]
> Does this change make sense? If not, please correct, then I publish the
> updated PDF.

The phrase "Linking against the Vask library is \$(VASKLIB) \$(CURSES)"
isn't grammatically correct. It should probably say something like
"Linking against the Vask library is performed using \$(VASKLIB)
\$(CURSES)"

Apart from that, it's OK.