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#ifndef __ALT_ERRNO_H__
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#define __ALT_ERRNO_H__
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/******************************************************************************
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*                                                                             *
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* License Agreement                                                           *
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*                                                                             *
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* Copyright (c) 2004 Altera Corporation, San Jose, California, USA.           *
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* All rights reserved.                                                        *
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*                                                                             *
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* Permission is hereby granted, free of charge, to any person obtaining a     *
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* copy of this software and associated documentation files (the "Software"),  *
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* to deal in the Software without restriction, including without limitation   *
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,    *
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* and/or sell copies of the Software, and to permit persons to whom the       *
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* Software is furnished to do so, subject to the following conditions:        *
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*                                                                             *
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* The above copyright notice and this permission notice shall be included in  *
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* all copies or substantial portions of the Software.                         *
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*                                                                             *
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  *
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,    *
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE *
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER      *
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING     *
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER         *
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* DEALINGS IN THE SOFTWARE.                                                   *
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*                                                                             *
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* This agreement shall be governed in all respects by the laws of the State   *
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* of California and by the laws of the United States of America.              *
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*                                                                             *
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* Altera does not recommend, suggest or require that this reference design    *
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* file be used in conjunction or combination with any other product.          *
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******************************************************************************/
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/******************************************************************************
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*                                                                             *
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* THIS IS A LIBRARY READ-ONLY SOURCE FILE. DO NOT EDIT.                       *
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*                                                                             *
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******************************************************************************/
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/*
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 * errno is defined in <errno.h> so that it uses the thread local version
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 * stored in the location pointed to by "_impure_ptr". This means that the
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 * accesses to errno within the HAL library can cause the entirety of
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 * of the structure pointed to by "_impure_ptr" to be added to the
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 * users application. This can be undesirable in very small footprint systems.
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 *
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 * To avoid this happening, the HAL uses the macro ALT_ERRNO, defined below,
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 * to access errno, rather than accessing it directly. This macro will only
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 * use the thread local version if some other code has already caused it to be
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 * included into the system, otherwise it will use the global errno value.
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 *
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 * This causes a slight increases in code size where errno is accessed, but
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 * can lead to significant overall benefits in very small systems. The
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 * increase is inconsequential when compared to the size of the structure
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 * pointed to by _impure_ptr.
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 *
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 * Note that this macro accesses __errno() using an externally declared
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 * function pointer (alt_errno). This is done so that the function call uses the
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 * subroutine call instruction via a register rather than an immediate address.
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 * This is important in the case that the code has been linked for a high
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 * address, but __errno() is not being used. In this case the weak linkage
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 * would have resulted in the instruction: "call 0" which would fail to link.
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 */
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extern int* (*alt_errno) (void);
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/* Must define this so that values such as EBADFD are defined in errno.h. */
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#define __LINUX_ERRNO_EXTENSIONS__
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#include <errno.h>
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#include "alt_types.h"
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#undef errno
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extern int errno;
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static ALT_INLINE int* alt_get_errno(void)
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{
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  return ((alt_errno) ? alt_errno() : &errno);
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}
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#define ALT_ERRNO *alt_get_errno()
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#endif /* __ALT_ERRNO_H__ */

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