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SubjectRe: 2.4.0-test9: minixfs causing oopsen when out of inodes
Date
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Daniel Phillips <news-innominate.list.linux.kernel@innominate.de> said:

[...]

> It would be nice if we could return a struct consisting of the error and
> result. I'm not sure if this is allowed in C now or not. It didn't
> work when I tried it with gcc: it seems to consider a struct-valued
> function to be a void-valued. Odd.

Odd? It works, has to: It's part of ANSI C. It is implemented by giving the
function a (hidden) pointer to a struct to be filled in, so this is much
slower than just stuffing a value into a register and returning. Plus it
won't work for syscalls with their arguments in registers, for obvious
reasons. Check this out (i686, RH 6.9.5 using kgcc and gcc give right
results):

#include <stdio.h>

struct s {
int error, result;
};
struct s f();

main()
{
struct s x = {0, 0};
x = f();
printf("error: %d, result: %d\n", x.error, x.result);
}
struct s f()
{
struct s xx;
xx.error = 1;
xx.result = 117;
return xx;
}--
Horst von Brand vonbrand@sleipnir.valparaiso.cl
Casilla 9G, Vin~a del Mar, Chile +56 32 672616
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