Trying to understand the Angband 3.X source code

[nppangband]

I have a bug that should be simple to fix, but I don't know where to do it.

The game crashes if I use the up, down, left, or right direction keys on my keyboard without the numlock on, but the diagonal direction keys work fine. It crashes on this line, in textui_process_command.

assert(p_ptr->command_cmd >= CHAR_MIN && p_ptr->command_cmd <= CHAR_MAX);

If the numlock is on, the p_ptr->command is 59, and if numlock is off, the direction keys are between 138-141, and the game crashes. Again, the diagonal keys work fine either way

Isn't there a pref file that converts certain keyboard commands like this? I know the 138 is above the 127 limit, but I can't figure out why it would be crashing the game. I have assert.h declared in h-basic.h just like in Angband.

Any thoughts or suggestions? I am stumped. Thanks.

[Pete Mack]

MSVC doesn't support full c99, but it does support the intersection of c99 with C++.
So bool is ok, but it's a built-in. (Dont' include stdbool.h)

[zaimoni]

Requiring C99 means dropping support for both MSVC (C89 compiler only) and native MingW32 (recent standard header releases don't compile as C99).

[Pete Mack]

A better workaround is to ditch all the stuff around bool, and change the compiler option -c89... to -c99

Then do a global replace TRUE by true and FALSE by false.
The messing around with non-standard boolean types is a highly undesirable archaism.

[zaimoni]

"bool" doesn't get redefined-- the #define bool bool_hack means that "bool_hack" is defined later, and everywhere in Angband that uses "bool" is actually using "bool_hack". I believe this is to work around people trying to use C++ compilers with Angband that define their own bool types.

A correct workaround is
1) ditch the #define (which invokes undefined behavior all versions of C++)
2) only bother with typedef'ing bool in C
3) Keep the rest of the code.

[nppangband]

"bool" doesn't get redefined-- the #define bool bool_hack means that "bool_hack" is defined later, and everywhere in Angband that uses "bool" is actually using "bool_hack". I believe this is to work around people trying to use C++ compilers with Angband that define their own bool types.

You are right. I know you & the the vanilla dev team know much more about this than I do. I can make the Angband source do what I want, but that is the limit of my programming knowledge.

That line gave me half of a page of compiler errors. "bool_hack" doesn't seem to be defined or exist anywhere else in the angband source. Actually, according to google, it doesn't exist anywhere else in the world either. So I removed it and all the compiler errors went away. Am I missing something & do I need bool_hack defined?

Am I reading that other code correctly? It looks like the line before undefines bool, and a couple lines later, if HAVE_STDBOOL_H, bool is defined by stdbool.h, and if I don't, it is defined as a bool. So why would bool_hack need to be defined?

Thanks.

[takkaria]

In looking at h-basic.h, line 157 of the code is redundant:

155 * C++ defines its own bool type, so we hack around it */
156 #undef bool
157 #define bool bool_hack

a coule lines later, bool is re-defined anyway, either through stdbool.h, or it is defined as a char for the systems that don't have STDBOOH_H...

"bool" doesn't get redefined-- the #define bool bool_hack means that "bool_hack" is defined later, and everywhere in Angband that uses "bool" is actually using "bool_hack". I believe this is to work around people trying to use C++ compilers with Angband that define their own bool types.

[nppangband]

Yep. There is no reason to code to a 20 year old standard when a 10 year old standard is available.

In looking at h-basic.h, line 157 of the code is redundant:

155 * C++ defines its own bool type, so we hack around it */
156 #undef bool
157 #define bool bool_hack

a coule lines later, bool is re-defined anyway, either through stdbool.h, or it is defined as a char for the systems that don't have STDBOOH_H...

/*
* Use a real bool type where possible
*/
#ifdef HAVE_STDBOOL_H

#include <stdbool.h>

#define TRUE true
#define FALSE false

#else

/* Use a char otherwise */
typedef char bool;

#undef TRUE
#undef FALSE

#define TRUE 1
#define FALSE 0

[nppangband]

'\xff' is (or should be) a character constant, kind of like '\n' or '\011'. In this case it's the number 255, aka 0377 in octal notation, aka 0xFF in hex notation.

I understand the problem now. It isn't the constant, but the fact that the Angband code places that code into a signed char variable. It was warning me that I was putting a value of 255 into a variable with a range of -127 to 128. When I changed the varible key in the structure ui_event_data (ui-event.h) to an unsigned character my compiler stopped complaining. Is that variable intended to hold values from -127 to -1?

[Pete Mack]

Current Angband coding guidelines target C89, so C99's bool is not available.

It's worth asking Takk about this, I think.

Yep. There is no reason to code to a 20 year old standard when a 10 year old standard is available.

[nppangband]

OK, gonig back to basics, what files are needed to compile Angband version 3.1.2 v2 on windows. If I get that going with LCC_win32, I can see what warnings come up.

I assume:

angband.rc

in the src directory:
the files attack.c through load.c. Is load-old.c needed?
main-win.c
files option.c through z-virt.c

now, for the src/subdirectories:
doc - nothing?
gtk - nothing?
lcc - nothing?
monster - melee1, melee2, monster1, monster 2
nds - nothing?
object - identify.c through randart.c
osx - nothing
player - calcs.c, timed.c, and util.c (note here LCC_win fails becaule util.c has the same name as hte file in the src directory. All files have to have different names regardless of which directory they are in)
tests - nothing? There are three files, smaple.c, z-file.c, and z-tets.c. Are these experimental, or should they be included?
win - readdib.c

I would experiment with this, but the feature to delete a *.c file from a makefile in LCC_win is broken. I can add them, but if I need to delete a file I have to start all over.

[nppangband]

Current Angband coding guidelines target C89, so C99's bool is not available.

It's worth asking Takk about this, I think.

Line 155 of h-basic.h has this:

/* C++ defines its own bool type, so we hack around it */
#undef bool
#define bool bool_hack

Then a couple lines later, there is this:

/*
* Use a real bool type where possible
*/
#ifdef HAVE_STDBOOL_H

#include <stdbool.h>

#define TRUE true
#define FALSE false

#else

/* Use a char otherwise */
typedef char bool;

and around line 50 of the same file, there is this....about STDBOOL...

/*
* Using C99, assume we have stdint and stdbool
*/
# if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
# define HAVE_STDINT_H
# define HAVE_STDBOOL_H
# endif

and at that point my little brain explodes..... I have no clue what is going on there. I assume it is an attempt to standardize the definition of bool for certain operating systems and compilers. But I doubt I could even understand it if somebody tried to explain it to me.

[d_m]

@jeff--
(And why there's a #define for bool in the first place is beyond me. It's a standard data type in C99 and later.)

Current Angband coding guidelines target C89, so C99's bool is not available.

It's worth asking Takk about this, I think.

[Pete Mack]

@jeff--
just about everyone uses gcc (MINGW on Windows) for compiling angband, though lcc is supposed to work too. I agree that redefines of bool are a much worse sign. (And why there's a #define for bool in the first place is beyond me. It's a standard data type in C99 and later.)

[ekolis]

If you use mingw/msys, you can just use the makefiles out of the box as if you were in Linux... if you're looking for an actual IDE, there's Visual C++ Express; I successfully got angband to compile in it after a bit of finagling, and I can send you the project files necessary if you'd like!