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From: rmathew@hotmail.com To: gcc-gnats@gcc.gnu.org Cc: rmathew@hotmail.com Subject: c++/8656: Unable to assign function with __attribute__ and pointer return type to an appropriate variable Date: Thu, 28 Nov 2002 07:31:00 -0000 [thread overview] Message-ID: <20021120105704.21723.qmail@sources.redhat.com> (raw) >Number: 8656 >Category: c++ >Synopsis: Unable to assign function with __attribute__ and pointer return type to an appropriate variable >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: rejects-legal >Submitter-Id: net >Arrival-Date: Wed Nov 20 03:06:03 PST 2002 >Closed-Date: >Last-Modified: >Originator: rmathew@hotmail.com >Release: GCC 3.2 >Organization: >Environment: MinGW, Cygwin and Linux(x86) (and possibly other x86-32 targets) >Description: Consider the following source code saved in file "bar.c": --------------------------- 8< --------------------------- extern int * (__attribute__((stdcall)) *fooPtr)( void); int * __attribute__((stdcall)) myFn01( void) { return 0; } void snafu( void) { fooPtr = myFn01; } --------------------------- 8< --------------------------- Running "g++ -c bar.c" gives: --------------------------- 8< --------------------------- bar.c: In function `void snafu()': bar.c:7: invalid conversion from `int*(*)()' to `int*(*)()' --------------------------- 8< --------------------------- However, running "gcc -c bar.c" creates no such problems. With reference to the source code given above, here're a few more observations: 1. This problem is not shown by the 2.95.3 g++. 2. If the definition of myFn01 above is changed to a declaration or if a declaration for the same is added before it, the problem disappears. 3. The problem appears only if the return type is of the kind "xyz *" - if there's a "typedef int *intptr;" and we use "intptr" instead of "int *" for myFn01, the problem disappears. 4. The problem can also be circumvented by putting the attribute and the function name together in parentheses like "int * (__attribute__((stdcall)) myFn01)( void)". 5. The problem does not come if all the "stdcall" instances are replaced by "cdecl", but it reappears if they are replaced by "fastcall". 6. Both Borland C/C++ 5.5 and MSVC++ 6.2 compile this code perfectly (after using the MS equivalent "__stdcall"). Lastly, this looks very similar to PR 6626, but IMHO is different - the syntax and semantics are perfectly valid in this case as far as I can see. >How-To-Repeat: Just save the sample code given above as file "bar.c" (or whatever) and run "g++ -c" on it. >Fix: >Release-Note: >Audit-Trail: >Unformatted:
next reply other threads:[~2002-11-20 11:06 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-11-28 7:31 rmathew [this message] 2002-12-05 5:54 ehrhardt
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