source: trunk/packages/xen-3.1/xen-3.1/extras/mini-os/include/err.h @ 34

#ifndef _ERR_H
#define _ERR_H

#include <errno.h>

/*
 * Kernel pointers have redundant information, so we can use a
 * scheme where we can return either an error code or a dentry
 * pointer with the same return value.
 *
 * This should be a per-architecture thing, to allow different
 * error and pointer decisions.
 */
#define IS_ERR_VALUE(x) ((x) > (unsigned long)-1000L)

static inline void *ERR_PTR(long error)
{
        return (void *) error;
}

static inline long PTR_ERR(const void *ptr)
{
        return (long) ptr;
}

static inline long IS_ERR(const void *ptr)
{
        return IS_ERR_VALUE((unsigned long)ptr);
}

#endif /* _LINUX_ERR_H */