Hello,
śr., 3 mar 2021 o 18:10 Eric Bollengier <e...@baculasystems.com> napisał(a):
> Hello Radek,
>
> On 3/3/21 17:40, Radosław Korzeniewski wrote:
> > Hello,
> >
> > The readline manual (from Debian) gives:
> >
> > READLINE(3)
> >
> > Library Functions Manual
> >
> > READLINE(3)
> >
> > NAME
> > readline - get a line from a user with editing
> >
> > SYNOPSIS
> > #include <stdio.h>
> > #include <readline/readline.h>
> > #include <readline/history.h>
> >
> > So, I assume that a correct way to include readline headers is as above.
> > But is this Linux specific?
>
> Yes, this is specific and probably some version of linux only (recent
> ones, but probably not old ones, or the one installed manually).
>
Debian 9 and readline 7.0 is far from "recent". I'm not sure if you can
install readline manually using include location other than
"*/readline/readline.h".
To verify that I compiled some readline library starting from version 2.0
(released in 1994) then 4.0, 5.0, 6.0. Every time (except ver 2.0 which
does not support this configure parameter) the library
uses --includedir=... parameter + "readline" directory for header files
location.
# ls -l /opt/readline-*/*/readline.h /usr/local/include/*/readline.h
-rw-r--r-- 1 root root 24120 Mar 3 20:30
/opt/readline-4.0/include/readline/readline.h
-rw-r--r-- 1 root root 33704 Mar 3 20:33
/opt/readline-5.0/include/readline/readline.h
-rw-r--r-- 1 root root 35121 Mar 3 20:35
/opt/readline-6.0/include/readline/readline.h
-rw-r--r-- 1 root staff 24120 Mar 3 20:29
/usr/local/include/readline/readline.h
Let's check the readline-6.0 installdirs target:
installdirs: $(srcdir)/support/mkinstalldirs
-$(SHELL) $(srcdir)/support/mkinstalldirs $(DESTDIR)$(includedir) \
$(DESTDIR)$(includedir)/readline $(DESTDIR)$(libdir) \
$(DESTDIR)$(infodir) $(DESTDIR)$(man3dir)
It "mkinstalldirs" for $(DESTDIR)$(includedir)/readline. So headers are
always installed at: "*/readline/" directory.
> > I'm asking as Bacula uses:
> >
> > #include "readline.h"
> > #include "history.h"
> >
> > which in my understanding is incorrect.
>
> This is not incorrect, everything depends on the ./configure detection,
> it includes the different path to the readline via something like CFLAGS
> or an other Makefile variable. Changing these two lines requires to
> update the configure and test on many platforms. Did you see a problem
> while compiling ?
>
It is incorrect as the readline.h and history.h are external to Bacula so
it should not use "local" includes.
> > What do you think?
>
> If all systems are using it, it's ok, but I believe that it's not the
> case. Systems where the readline is directly inside include/ will not
> compile with <readline/readline.h> while they can compile with the
> current code. Some people might call that a regression :-)
>
The question is why would a readline be available at an incorrect location
not designed by readline developers?
If readline developers designed his library to be used as
<readline/readline.h> then in my opinion we use it incorrectly, right?
I'm pretty sure that we use it incorrectly as the whole code goes like this:
#ifdef HAVE_READLINE
#define READLINE_LIBRARY 1
#include "readline.h"
#include "history.h"
...
But our code is not a readline library code, so why do we define this
macro: READLINE_LIBRARY at all?
What I understand from the readline code is that this macro is used to
distinguish between "internal" and "public" usages.
We should use a public interface of readline, right? So if public then
readline developers designed it as: <readline/*.h>
What do you think?
--
Radosław Korzeniewski
rados...@korzeniewski.net
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