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| author | Neil Booth <neil@gcc.gnu.org> | 2003-05-04 20:03:55 +0000 |
|---|---|---|
| committer | Neil Booth <neil@gcc.gnu.org> | 2003-05-04 20:03:55 +0000 |
| commit | a8eb6044a9468a56cab63890820e17101ce8fd64 (patch) | |
| tree | db0e598a611fbe90ebcaf267b9665fd02c67a70f /gcc/doc/cpp.texi | |
| parent | 09780dfb652960d422da1c5a9d81dc536cdf09f4 (diff) | |
| download | gcc-a8eb6044a9468a56cab63890820e17101ce8fd64.zip gcc-a8eb6044a9468a56cab63890820e17101ce8fd64.tar.gz gcc-a8eb6044a9468a56cab63890820e17101ce8fd64.tar.bz2 | |
cppinit.c (cpp_create_reader, [...]): Warn about trigraphs unless explicity set or -trigraphs.
* cppinit.c (cpp_create_reader, post_options): Warn about
trigraphs unless explicity set or -trigraphs.
* cpplex.c (warn_in_comment): New.
(_cpp_process_line_notes): Better handling of -Wtrigraphs.
(_cpp_skip_block_comment): Add call to _cpp_process_line_notes.
* doc/cppopts.texi, doc/cpp.texi: Update.
testsuite:
* gcc.dg/cpp/Wtrigraphs.c: Update.
* gcc.dg/cpp/Wtrigraphs-2.c: New tests.
From-SVN: r66459
Diffstat (limited to 'gcc/doc/cpp.texi')
| -rw-r--r-- | gcc/doc/cpp.texi | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi index cf962c4..173e341 100644 --- a/gcc/doc/cpp.texi +++ b/gcc/doc/cpp.texi @@ -293,16 +293,18 @@ obsolete systems that lack some of C's punctuation to use C@. For example, @samp{??/} stands for @samp{\}, so @t{'??/n'} is a character constant for a newline. -Trigraphs are not popular and many compilers implement them incorrectly. -Portable code should not rely on trigraphs being either converted or -ignored. If you use the @option{-Wall} or @option{-Wtrigraphs} options, -GCC will warn you when a trigraph would change the meaning of your -program if it were converted. - -In a string constant, you can prevent a sequence of question marks from -being confused with a trigraph by inserting a backslash between the -question marks. @t{"(??\?)"} is the string @samp{(???)}, not -@samp{(?]}. Traditional C compilers do not recognize this idiom. +Trigraphs are not popular and many compilers implement them +incorrectly. Portable code should not rely on trigraphs being either +converted or ignored. With @option{-Wtrigraphs} GCC will warn you +when a trigraph may change the meaning of your program if it were +converted. @xref{Wtrigraphs}. + +In a string constant, you can prevent a sequence of question marks +from being confused with a trigraph by inserting a backslash between +the question marks, or by separating the string literal at the +trigraph and making use of string literal concatenation. @t{"(??\?)"} +is the string @samp{(???)}, not @samp{(?]}. Traditional C compilers +do not recognize these idioms. The nine trigraphs and their replacements are |