In the LWN discussion of the "ASCII" art in GCC 14 https://lwn.net/Articles/946733/#Comments there was some concern about the use of non-ASCII characters in the output.
Currently -fdiagnostics-text-art-charset defaults to "emoji". To better handle older terminals by default, this patch special-cases LANG=C to use -fdiagnostics-text-art-charset=ascii. Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu. Pushed to trunk as r14-4669-g04013e4464020b. gcc/ChangeLog: * diagnostic.cc (diagnostic_initialize): When LANG=C, update default for -fdiagnostics-text-art-charset from emoji to ascii. * doc/invoke.texi (fdiagnostics-text-art-charset): Document the above. --- gcc/diagnostic.cc | 13 +++++++++++-- gcc/doc/invoke.texi | 3 ++- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/gcc/diagnostic.cc b/gcc/diagnostic.cc index 03637459c56..6e46371b3b4 100644 --- a/gcc/diagnostic.cc +++ b/gcc/diagnostic.cc @@ -226,8 +226,17 @@ diagnostic_initialize (diagnostic_context *context, int n_opts) context->includes_seen = NULL; context->m_client_data_hooks = NULL; context->m_diagrams.m_theme = NULL; - diagnostics_text_art_charset_init (context, - DIAGNOSTICS_TEXT_ART_CHARSET_DEFAULT); + + enum diagnostic_text_art_charset text_art_charset + = DIAGNOSTICS_TEXT_ART_CHARSET_DEFAULT; + if (const char *lang = getenv ("LANG")) + { + /* For LANG=C, don't assume the terminal supports anything + other than ASCII. */ + if (!strcmp (lang, "C")) + text_art_charset = DIAGNOSTICS_TEXT_ART_CHARSET_ASCII; + } + diagnostics_text_art_charset_init (context, text_art_charset); } /* Maybe initialize the color support. We require clients to do this diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 7c5f81d9783..ef9d1fb8fe6 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -5681,7 +5681,8 @@ value further adds the possibility of emoji in the output (such as emitting U+26A0 WARNING SIGN followed by U+FE0F VARIATION SELECTOR-16 to select the emoji variant of the character). -The default is @samp{emoji}. +The default is @samp{emoji}, except when the environment variable @env{LANG} +is set to @samp{C}, in which case the default is @samp{ascii}. @opindex fdiagnostics-format @item -fdiagnostics-format=@var{FORMAT} -- 2.26.3