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Re: Creating a new port in C for use in guile
From: |
Ludovic Courtès |
Subject: |
Re: Creating a new port in C for use in guile |
Date: |
Thu, 04 Sep 2014 13:00:39 +0200 |
User-agent: |
Gnus/5.130011 (Ma Gnus v0.11) Emacs/24.3 (gnu/linux) |
Joshua Datko <address@hidden> skribis:
> I want to make a new Port. I would like to write the port implementation
> in C and use that port in scheme.
>
> I'm a bit confused on how to proceed though. From reading the docs, it
> seems I have to create a C function, in the form of an extension, that
> calls scm_make_port_type.
>
> However, the manual states [1] that the return value from
> scm_make_port_type is a scm_ptob_descriptor. I'm confused on how I
> instantiate this new port type to get a scm_port.
‘scm_make_port_type’ returns a number of the ‘scm_t_bits’ type. That
number identifies the port type internally.
Then, to instantiate a port of that type, use
‘scm_new_port_table_entry’:
--8<---------------cut here---------------start------------->8---
scm_t_bits port_type;
port_type = scm_make_port_type (...);
[...]
SCM port;
port = scm_new_port_table_entry (port_type);
--8<---------------cut here---------------end--------------->8---
Here’s a couple of examples:
http://git.savannah.gnu.org/cgit/guile.git/tree/libguile/r6rs-ports.c#n73
https://gitorious.org/gnutls/gnutls/source/12e50aa449a8f6bb7b2c2fa3c177812e463ea4c7:guile/src/core.c#L923
Hope this helps!
Ludo’.