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/**
* slibc — Yet another C library
* Copyright © 2015 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _UNISTD_H
#define _UNISTD_H
#include <slibc/version.h>
#include <slibc/features.h>
#define __NEED_ptrdiff_t
#include <bits/types.h>
/**
* Set the high end of the calling process's
* data segment.
*
* The high end is defined as the last byte
* in the segment plus 1.
*
* Using `brk` is highly discouraged. `malloc`,
* `calloc` and `free`, and its related functions,
* fall be used instead as they are much more
* conformable. Use of `brk` can couse errors
* when using `malloc`, `free`, &c. Thus, `brk`
* shall (bascially) only be used if you are
* writting an alterantive malloc-implementation.
*
* `brk` was marked LEGACY in SUSv2, and it
* was removed from the POSIX standard in revision
* POSIX.1-2001. It is however fundamental in
* implementing a fast `malloc`-implementation.
*
* @param address The process's new high end of its data segment.
* If lower than the current low end, nothing will
* happen and the function will return with a success
* status.
* @return Zero on succes, -1 on error. On error, `errno`
* is set to indicate the error.
*
* @throws ENOMEM The process can allocate the requested amount
* of memory. Either the process store limit would
* have been exceeded, RAM and swap memory would
* have been exhausted, or the request would cause
* the data segment to overlap another segment.
*/
int brk(void*) /* TODO implement brk */
__GCC_ONLY(__attribute__((warn_unused_result)));
/**
* Set and get the current high end of the calling
* process's data segment.
*
* There is some documents that state that the new,
* rather than the previous, high end is returned.
* Additionally, some documentions do not document
* possible failure. Thus only `sbrk(0)` is guaranteed
* to be portable. The return type differs between
* implementations; common return types are `int`,
* `ssize_t`, `ptrdiff_t`, `ptrdiff_t`, `intptr_t`,
* and `void*`. Note that `int` is
* microarchitecture-portable.
*
* `sbrk` was marked LEGACY in SUSv2, and it
* was removed from the POSIX standard in revision
* POSIX.1-2001. It is however fundamental in
* implementing a fast `malloc`-implementation.
*
* @param delta The incremant of the size of the data segment,
* zero means that the high end shall not be moved
* (thus the current high end is returned,) a
* positive value will cause the segment to grow,
* a negative value will cause the segment to shrink.
* @return The previous high end. `(void*)-1` is returned on error.
*
* @throws ENOMEM The process can allocate the requested amount
* of memory. Either the process store limit would
* have been exceeded, RAM and swap memory would
* have been exhausted, or the request would cause
* the data segment to overlap another segment.
*/
void* sbrk(ptrdiff_t) /* TODO implement sbrk */
__GCC_ONLY(__attribute__((warn_unused_result)));
#endif
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