[Bug c/46115] New: Feature request: anonymous functions (complementing anon aggregates)

[Bug c/46115] New: Feature request: anonymous functions (complementing anon aggregates)

[robert.staudinger at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46115

           Summary: Feature request: anonymous functions (complementing
                    anon aggregates)
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: robert.staudinger@gmail.com


It would be great if GCC would consider addition of anonymous functions along
the lines of anonymous aggreates, i.e. deferring the formal parameters from the
preceding cast expression.

Example:

void (*func_ptr)(int) = (void (*)(int i)) { printf ("%i", i); };

[Bug c/46115] Feature request: anonymous functions (complementing anon aggregates)

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46115

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-10-21 18:38:31 UTC ---
This sounds like C++ lambda functions.

Second,  I think this is a bad idea for C.

[Bug c/46115] Feature request: anonymous functions (complementing anon aggregates)

[robert.staudinger at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46115

--- Comment #2 from Rob Staudinger <robert.staudinger at gmail dot com> 2010-10-22 08:33:46 UTC ---
There obviously is some relation, but this proposal evades syntactical
overloading of operators, unlike C++ lambda functions or LLVM blocks.

[Bug c/46115] Feature request: anonymous functions (complementing anon aggregates)

[robert.staudinger at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46115

--- Comment #3 from Rob Staudinger <robert.staudinger at gmail dot com> 2010-10-25 07:31:59 UTC ---
For the record, this is already possible using bracketed expressions, but the
syntactical sugar of not having to pick a function name would be great.

#include <stdio.h>
#include <stdlib.h>

int
main (int argc, char **argv)
{
  void (*func_ptr)(int) = ({ void func(int i) { printf ("%i\n", i); };
                             func;
                           });

  func_ptr (3);

  return EXIT_SUCCESS;
}

[Bug c/46115] Feature request: anonymous functions (complementing anon aggregates)

[shawn at churchofgit dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46115

Shawn Landden <shawn at churchofgit dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |shawn at churchofgit dot com

--- Comment #4 from Shawn Landden <shawn at churchofgit dot com> ---
There is also the Apple blocks extension to C.
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1370.pdf
http://clang.llvm.org/docs/Block-ABI-Apple.html#history

[Bug c/46115] Feature request: anonymous functions (complementing anon aggregates)

[shawn at churchofgit dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46115

--- Comment #5 from Shawn Landden <shawn at churchofgit dot com> ---
http://mackyle.github.io/blocksruntime/#download

[Bug c/46115] Feature request: anonymous functions (complementing anon aggregates)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46115

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Rob Staudinger from comment #3)
> For the record, this is already possible using bracketed expressions, but
> the syntactical sugar of not having to pick a function name would be great.

Actually that is not valid as func is local to that scope and now it escapes.

[Bug c/46115] Feature request: anonymous functions (complementing anon aggregates)

[muecker at gwdg dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46115

Martin Uecker <muecker at gwdg dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |muecker at gwdg dot de

--- Comment #7 from Martin Uecker <muecker at gwdg dot de> ---
The documentation implies that the pointer escaping the scope and calling the
function is safe as long as it does not access a variable of the enclosing
function that went out of scope.