From: Leo Butler <Leo.Butler@umanitoba.ca>
To: Org Mode Mailing List <emacs-orgmode@gnu.org>
Subject: [PATCH] float format specifier in ob-C.el
Date: Wed, 31 May 2023 15:36:58 +0000 [thread overview]
Message-ID: <87pm6g4ina.fsf@t14.reltub.ca> (raw)
[-- Attachment #1: Type: text/plain, Size: 513 bytes --]
In ob-C.el, line 339 has the format specifier
(`floatp '("double" "%f"))
to print literal floats. However, that format specifier rounds, which
can result in errors. I think the correct approach is to print the
float without rounding or padding or trying to guess at the desired
accuracy (and let the compiler do whatever is needed):
(`floatp '("double" "%s"))
Attached is a patch with a test that illustrates the problem (it fails
on HEAD but passes with the patch).
Leo
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-On-ltb-ob-max-ob-C-float-format.patch --]
[-- Type: text/x-diff; name="0001-On-ltb-ob-max-ob-C-float-format.patch", Size: 1619 bytes --]
diff --git a/lisp/ob-C.el b/lisp/ob-C.el
index 3a6e99623..6b9898ebb 100644
--- a/lisp/ob-C.el
+++ b/lisp/ob-C.el
@@ -339,7 +339,7 @@ FORMAT can be either a format string or a function which is called with VAL."
(type
(pcase basetype
(`integerp '("int" "%d"))
- (`floatp '("double" "%f"))
+ (`floatp '("double" "%s"))
(`stringp
(list
(if (eq org-babel-c-variant 'd) "string" "const char*")
diff --git a/testing/examples/ob-C-test.org b/testing/examples/ob-C-test.org
index c7a96f665..58ace91de 100644
--- a/testing/examples/ob-C-test.org
+++ b/testing/examples/ob-C-test.org
@@ -60,6 +60,12 @@
return 0;
#+end_src
+#+source: float_var
+#+begin_src cpp :var x=1.123456789012345678 :includes "<iostream>" :results silent
+double y = 1.123456789012345678;
+std::cout << (x == y);
+#+end_src
+
* Array
:PROPERTIES:
:ID: 2df1ab83-3fa3-462a-a1f3-3aef6044a874
diff --git a/testing/lisp/test-ob-C.el b/testing/lisp/test-ob-C.el
index b6dbed8e3..41b500d5b 100644
--- a/testing/lisp/test-ob-C.el
+++ b/testing/lisp/test-ob-C.el
@@ -95,6 +95,13 @@
(org-babel-next-src-block 10)
(should (= 42 (org-babel-execute-src-block))))))
+(ert-deftest ob-C/float-var ()
+ "Test of a string variable"
+ (if (executable-find org-babel-C++-compiler)
+ (org-test-at-id "fa6db330-e960-4ea2-ac67-94bb845b8577"
+ (org-babel-next-src-block 11)
+ (should (= 1 (org-babel-execute-src-block))))))
+
(ert-deftest ob-C/table ()
"Test of a table output"
(if (executable-find org-babel-C++-compiler)
next reply other threads:[~2023-05-31 15:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-31 15:36 Leo Butler [this message]
2023-06-01 8:27 ` [PATCH] float format specifier in ob-C.el Ihor Radchenko
2023-06-01 19:00 ` Leo Butler
2023-06-02 7:25 ` Ihor Radchenko
2023-06-02 13:50 ` Leo Butler
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.orgmode.org/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87pm6g4ina.fsf@t14.reltub.ca \
--to=leo.butler@umanitoba.ca \
--cc=emacs-orgmode@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).