From: burlen <burlen.loring@gmail.com>
To: Ian Lance Taylor <iant@google.com>
Cc: gcc-help@gcc.gnu.org
Subject: Re: fortran 90 passing user defined type member to a c fucntion
Date: Sun, 28 Mar 2010 03:12:00 -0000 [thread overview]
Message-ID: <4BAE42FF.7020200@gmail.com> (raw)
In-Reply-To: <mcrwrwyr70n.fsf@dhcp-172-17-9-151.mtv.corp.google.com>
Ian Lance Taylor wrote:
> burlen <burlen.loring@gmail.com> writes:
>
>
>> When calling a c function from a fortran 90 program with members of a
>> user defined types for output arguments of the called subroutine the
>> user defined types aren't being modified as they should be (according
>> to my understanding).
>>
>
> When you call a C function, you get the C rules. It doesn't matter
> whether you are calling it from Fortran or not. In C, a modification
> of an argument is not reflected back to the caller.
>
> Ian
>
In my understanding, Fortran unless otherwise instructed is supposed to
pass by address. In the c function modifying the data pointed to should
do just that, and be visible to the caller. What I don't understand is
why passing the member of a user defined type behaves as if it's passed
by value in this case, while passing the corresponding native type is
passed by address and works as expected.
next prev parent reply other threads:[~2010-03-27 17:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-26 22:02 burlen
2010-03-27 6:28 ` Ian Lance Taylor
2010-03-28 3:12 ` burlen [this message]
2010-03-28 7:29 ` Ian Lance Taylor
2010-03-28 20:22 ` burlen
2010-03-28 20:52 ` Tim Prince
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