Re: ffi-helper: looking for C libraries to try

[Matt Wette]

> On Jul 15, 2017, at 6:15 AM, Matt Wette <address@hidden> wrote:
> 
> 
>> On Jul 14, 2017, at 9:35 PM, Matt Wette <address@hidden> wrote:
>> 
>> 
>>> On Jul 14, 2017, at 5:44 PM, Amirouche Boubekki <address@hidden> wrote:
>>> 
>>> On 2017-07-15 01:17, Matt Wette wrote:
>>>> I tried git2 but those headers are too
>>>> broken.
>>> 
>>> What do you mean by "too broken"? Maybe it will be easier in the long run 
>>> to maintain our own version of the headers than manually bind everything. 
>>> Even if it requires to create a shim layer in scheme to have a proper set 
>>> of bindings that schemer will enjoy. Also, git is a good candidate since 
>>> there are some tests already in guile-git [1].
>> 
>> Maybe another bug in my CPP.  
>> 
>> (define-ffi-module (libgit2)
>> #:include '("git2.h")
>> #:inc-dirs '("/opt/local/include")
>> #:library '("git2")
>> )
>> 
>> mwette$ guild compile-ffi libgit2.ffi 
>> (unknown):1: not found: “common.h"
>> 
> 
> I claim libgit2 headers are broken.  The standard says, essentially, “how 
> headers are located is implementation defined”.
> 
> The file …/include/git2.h states:
> #include “git2/annotated_commit.h”
> #include “git2/common.h”
> …
> 
> But the file include/git2/annotated_commit.h states:
> #include “common.h”
> 
> Note this is “common.h" not “git2/common.h” How does gcc find common.h?  
> The directory include/git2 is not in the include path.  
> These are the ugly, undocumented, non-standard items that scare me.

I found a reference for include file searching in gcc: 
        https://gcc.gnu.org/onlinedocs/cpp/Search-Path.html

I have returned to working on libgit2.  It turns out glib uses this, and 
include_next as well.
So I have added this behavior plus include_next.  Test/debug of the fyi-helper 
goes on …

I have been able too compile-ffi, almost everything from cairo, gdbm, sqlite3.  
Now working on rsvp and libgit2. 

Not supported so far is va-args.  That will require some help from the user.  
(Libffi does not support va-args.)

Matt