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From: loewis@informatik.hu-berlin.de To: gcc-gnats@gcc.gnu.org Cc: boehme@informatik.hu-berlin.de Subject: preprocessor/6781: Creating header-names is not possible Date: Thu, 23 May 2002 03:26:00 -0000 [thread overview] Message-ID: <200205231016.g4NAGB0C010211@paros.informatik.hu-berlin.de> (raw) >Number: 6781 >Category: preprocessor >Synopsis: Creating header-names is not possible >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: change-request >Submitter-Id: net >Arrival-Date: Thu May 23 03:26:00 PDT 2002 >Closed-Date: >Last-Modified: >Originator: >Release: 3.1 >Organization: HUB >Environment: System: SunOS paros 5.9 Beta_Refresh sun4u sparc SUNW,Sun-Blade-1000 Architecture: sun4 host: sparc-sun-solaris2.8 build: sparc-sun-solaris2.8 target: sparc-sun-solaris2.8 configured with: ../configure --host=sparc-sun-solaris2.8 --enable-shared --enable-threads --with-cpu=v8 --with-gnu-ld --with-gnu-as --enable-version-specific-runtime-libs >Description: The code #define inc2(a,b) <##a##.##b##> #define INC(X) inc2(X,h) #include INC(stdio) int main() { printf("Hallo"); } first gives a warning, then reports stdio: No such file or directory The intent of this code is to create a header-name token (2.8) through token pasting. In an pedantic interpretation, this invokes undefined behaviour, since it creates intermediate tokens which are invalid preprocessing tokens. GCC should support this code as an extension (performing an #include of stdio.h), and only warn about this problem when pedantic (since it is undefined behaviour, no diagnostics is required by the standard). More specifically, it normally should only emit the warning if interpreting the full ## sequence produces an invalid token. Havin this extension is desirable, because a) nearly every other compiler supports it (even though just because the compilers fail to notice the problem); b) this is the best approach to deal with portability of CORBA applications, where different IDL compilers emit differently named header files. >How-To-Repeat: Compile the included program. >Fix: >Release-Note: >Audit-Trail: >Unformatted:
next reply other threads:[~2002-05-23 10:26 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-05-23 3:26 loewis [this message] 2002-05-23 3:49 neil 2002-05-23 3:53 neil 2002-05-23 7:26 Martin v. Löwis 2002-05-23 9:38 neil
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