public inbox for gcc-cvs-wwwdocs@sourceware.org help / color / mirror / Atom feed
From: David Malcolm <dmalcolm@sourceware.org> To: gcc-cvs-wwwdocs@gcc.gnu.org Subject: gcc-wwwdocs branch master updated. df48cfe754f3ec94c83955c29133baa9580bc1df Date: Tue, 6 Oct 2020 15:04:07 +0000 (GMT) [thread overview] Message-ID: <20201006150407.D2FFB3952C3A@sourceware.org> (raw) This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "gcc-wwwdocs". The branch, master has been updated via df48cfe754f3ec94c83955c29133baa9580bc1df (commit) from 693cc9122512b580926acacf2b7516b0a23b770a (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit df48cfe754f3ec94c83955c29133baa9580bc1df Author: David Malcolm <dmalcolm@redhat.com> Date: Tue Oct 6 11:02:22 2020 -0400 gcc-11/changes: Add notes about column number changes diff --git a/htdocs/gcc-11/changes.html b/htdocs/gcc-11/changes.html index 64655120..e2a32e51 100644 --- a/htdocs/gcc-11/changes.html +++ b/htdocs/gcc-11/changes.html @@ -72,6 +72,45 @@ a work-in-progress.</p> control if function entries and exits should be instrumented.</li> </ul> </li> + <li> + <p> + In previous releases of GCC, the "column numbers" emitted in diagnostics + were actually a count of bytes from the start of the source line. This + could be problematic, both because of: + </p> + <ul> + <li>multibyte characters (requiring more than one byte to encode), and</li> + <li>multicolumn characters (requiring more than one column to display in a monospace font)</li> + </ul> + <p> + For example, the character π ("GREEK SMALL LETTER PI (U+03C0)") + occupies one column, and its UTF-8 encoding requires two bytes; the + character 🙂 ("SLIGHTLY SMILING FACE (U+1F642)") occupies two + columns, and its UTF-8 encoding requires four bytes. + </p> + <p> + In GCC 11 the column numbers default to being column numbers, respecting + multi-column characters. The old behavior can be restored using a new + option + <a href="https://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-column-unit">-fdiagnostics-column-unit=byte</a>. + There is also a new option + <a href="https://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-column-origin">-fdiagnostics-column-origin=</a>, + allowing the pre-existing default of the left-hand column being column + 1 to be overridden if desired (e.g. for 0-based columns). The output + of + <a href="https://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format">-fdiagnostics-format=json</a> + has been extended to supply both byte counts and column numbers for all source locations. + </p> + <p> + Additionally, in previous releases of GCC, tab characters in the source + would be emitted verbatim when quoting source code, but be prefixed + with whitespace or line number information, leading to misalignments + in the resulting output when compared with the actual source. Tab + characters are now printed as an appropriate number of spaces, using the + <a href="https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html#index-ftabstop">-ftabstop</a> + option (which defaults to 8 spaces per tab stop). + </p> + </li> </ul> <!-- .................................................................. --> ----------------------------------------------------------------------- Summary of changes: htdocs/gcc-11/changes.html | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) hooks/post-receive -- gcc-wwwdocs
reply other threads:[~2020-10-06 15:04 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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 * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20201006150407.D2FFB3952C3A@sourceware.org \ --to=dmalcolm@sourceware.org \ --cc=gcc-cvs-wwwdocs@gcc.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: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
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).