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ossc/software/sys_controller_bsp/HAL/inc/sys/alt_errno.h
2016-02-23 01:03:50 +02:00

88 lines
4.6 KiB
C

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