errno.h

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/* KallistiOS ##version##
 
   include/kos/errno.h
   Copyright (C) 2025 Paul Cercueil
 
*/
 
/** \file    kos/errno.h
    \brief   Errno helper functions.
    \ingroup errno
 
    This file contains functions and macros related to the 'errno' variable.
 
    \author Paul Cercueil
*/
 
#ifndef __KOS_ERRNO_H
#define __KOS_ERRNO_H
 
#include <errno.h>
 
/** \cond */
static inline void __errno_scoped_cleanup(int *e) {
    if(e)
        errno = *e;
}
 
#define ___errno_save_scoped(l) \
    int __scoped_errno_##l __attribute__((cleanup(__errno_scoped_cleanup))) = (errno)
 
#define __errno_save_scoped(l) ___errno_save_scoped(l)
/** \endcond */
 
/** \brief  Save the current 'errno' value until the block exit
 
    This macro will keep a copy of the current value of the errno variable, and
    will restore it once the execution exits the functional block in which the
    macro was called.
*/
#define errno_save_scoped() __errno_save_scoped(__LINE__)
 
/** \brief  Return errno if the value is non-zero, otherwise return zero
 
    This simple macro can be used to interface the functions that return 0 on
    success and -1 on error, with the actual error code stored in the errno
    variable.
 
    \param  x               The integer value to process
    \return                 0 on success, a positive errno code on error
*/
#define errno_if_nonzero(x) ((x) ? errno : 0)
 
#endif /* __KOS_ERRNO_H */