diff options
Diffstat (limited to 'gcc/doc/cpp.texi')
| -rw-r--r-- | gcc/doc/cpp.texi | 32 |
1 files changed, 17 insertions, 15 deletions
diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi index e271f51..f2de39a 100644 --- a/gcc/doc/cpp.texi +++ b/gcc/doc/cpp.texi @@ -274,11 +274,11 @@ the character in the source character set that they represent, then converted to the execution character set, just like unescaped characters. -In identifiers, characters outside the ASCII range can only be -specified with the @samp{\u} and @samp{\U} escapes, not used -directly. If strict ISO C90 conformance is specified with an option +In identifiers, characters outside the ASCII range can be specified +with the @samp{\u} and @samp{\U} escapes or used directly in the input +encoding. If strict ISO C90 conformance is specified with an option such as @option{-std=c90}, or @option{-fno-extended-identifiers} is -used, then those escapes are not permitted in identifiers. +used, then those constructs are not permitted in identifiers. @node Initial processing @section Initial processing @@ -503,8 +503,7 @@ In the 1999 C standard, identifiers may contain letters which are not part of the ``basic source character set'', at the implementation's discretion (such as accented Latin letters, Greek letters, or Chinese ideograms). This may be done with an extended character set, or the -@samp{\u} and @samp{\U} escape sequences. GCC only accepts such -characters in the @samp{\u} and @samp{\U} forms. +@samp{\u} and @samp{\U} escape sequences. As an extension, GCC treats @samp{$} as a letter. This is for compatibility with some systems, such as VMS, where @samp{$} is commonly @@ -584,15 +583,15 @@ Punctuator: @{ @} [ ] # ## @end smallexample @cindex other tokens -Any other single character is considered ``other''. It is passed on to -the preprocessor's output unmolested. The C compiler will almost -certainly reject source code containing ``other'' tokens. In ASCII, the -only other characters are @samp{@@}, @samp{$}, @samp{`}, and control +Any other single byte is considered ``other'' and passed on to the +preprocessor's output unchanged. The C compiler will almost certainly +reject source code containing ``other'' tokens. In ASCII, the only +``other'' characters are @samp{@@}, @samp{$}, @samp{`}, and control characters other than NUL (all bits zero). (Note that @samp{$} is -normally considered a letter.) All characters with the high bit set -(numeric range 0x7F--0xFF) are also ``other'' in the present -implementation. This will change when proper support for international -character sets is added to GCC@. +normally considered a letter.) All bytes with the high bit set +(numeric range 0x7F--0xFF) that were not succesfully interpreted as +part of an extended character in the input encoding are also ``other'' +in the present implementation. NUL is a special case because of the high probability that its appearance is accidental, and because it may be invisible to the user @@ -4179,7 +4178,10 @@ be controlled using the @option{-fexec-charset} and The C and C++ standards allow identifiers to be composed of @samp{_} and the alphanumeric characters. C++ also allows universal character names. C99 and later C standards permit both universal character -names and implementation-defined characters. +names and implementation-defined characters. In both C and C++ modes, +GCC accepts in identifiers exactly those extended characters that +correspond to universal character names permitted by the chosen +standard. GCC allows the @samp{$} character in identifiers as an extension for most targets. This is true regardless of the @option{std=} switch, |