stdlib.h

用于AVR单片机上的

/* Copyright (c) 2002, Marek Michalkiewicz
   Copyright (c) 2004, Joerg Wunsch

   Portions of documentation Copyright (c) 1990, 1991, 1993, 1994
   The Regents of the University of California.

   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are met:

   * Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.

   * Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in
     the documentation and/or other materials provided with the
     distribution.

   * Neither the name of the copyright holders nor the names of
     contributors may be used to endorse or promote products derived
     from this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.

  $Id: stdlib.h,v 1.22 2004/12/14 22:56:51 joerg_wunsch Exp $
*/

#ifndef _STDLIB_H_
#define	_STDLIB_H_ 1

#ifndef __ASSEMBLER__

#define __need_NULL
#define __need_size_t
#define __need_wchar_t
#include <stddef.h>

#ifndef __ptr_t
#define __ptr_t void *
#endif

#ifdef __cplusplus
extern "C" {
#endif

/** \defgroup avr_stdlib General utilities
    \code #include <stdlib.h> \endcode

    This file declares some basic C macros and functions as
    defined by the ISO standard, plus some AVR-specific extensions.
*/

/*@{*/
/** Result type for function div(). */
typedef struct {
	int quot;                   /**< The Quotient. */
	int rem;                    /**< The Remainder. */
} div_t;

/** Result type for function ldiv(). */
typedef struct {
	long quot;                  /**< The Quotient. */
	long rem;                   /**< The Remainder. */
} ldiv_t;

/** Comparision function type for qsort(), just for convenience. */
typedef int (*__compar_fn_t)(const void *, const void *);

#ifndef DOXYGEN

#ifndef __ATTR_CONST__
#define __ATTR_CONST__ __attribute__((__const__))
#endif

#ifndef __ATTR_MALLOC__
#define __ATTR_MALLOC__ __attribute__((__malloc__))
#endif

#ifndef __ATTR_NORETURN__
#define __ATTR_NORETURN__ __attribute__((__noreturn__))
#endif

#ifndef __ATTR_PURE__
#define __ATTR_PURE__ __attribute__((__pure__))
#endif

#endif

extern __inline__ void abort(void) __ATTR_NORETURN__;

/** The abort() function causes abnormal program termination to occur.
    In the limited AVR environment, execution is effectively halted
    by entering an infinite loop. */
extern __inline__ void
abort(void)
{
	for (;;);
}

/** The abs() function computes the absolute value of the integer \c i.
   \note The abs() and labs() functions are builtins of gcc.
*/
extern int abs(int __i) __ATTR_CONST__;
#ifndef DOXYGEN
#define	abs(__i) __builtin_abs(__i)
#endif

/** The labs() function computes the absolute value of the long integer
    \c i.
   \note The abs() and labs() functions are builtins of gcc.
*/
extern long labs(long __i) __ATTR_CONST__;
#ifndef DOXYGEN
#define labs(__i) __builtin_labs(__i)
#endif

/**
     The bsearch() function searches an array of \c nmemb objects, the
     initial member of which is pointed to by \c base, for a member
     that matches the object pointed to by \c key.  The size of each
     member of the array is specified by \c size.

     The contents of the array should be in ascending sorted order
     according to the comparison function referenced by \c compar.
     The \c compar routine is expected to have two arguments which
     point to the key object and to an array member, in that order,
     and should return an integer less than, equal to, or greater than
     zero if the key object is found, respectively, to be less than,
     to match, or be greater than the array member.

     The bsearch() function returns a pointer to a matching member of
     the array, or a null pointer if no match is found.  If two
     members compare as equal, which member is matched is unspecified.
*/
extern void *bsearch(const void *__key, const void *__base, size_t __nmemb,
		     size_t __size, int (*__compar)(const void *, const void *));

/* __divmodhi4 and __divmodsi4 from libgcc.a */
/**
     The div() function computes the value \c num/denom and returns
     the quotient and remainder in a structure named \c div_t that
     contains two int members named \c quot and \c rem.
*/
extern div_t div(int __num, int __denom) __asm__("__divmodhi4") __ATTR_CONST__;
/**
     The ldiv() function computes the value \c num/denom and returns
     the quotient and remainder in a structure named \c ldiv_t that
     contains two long integer members named \c quot and \c rem.
*/
extern ldiv_t ldiv(long __num, long __denom) __asm__("__divmodsi4") __ATTR_CONST__;

/**
     The qsort() function is a modified partition-exchange sort, or
     quicksort.

     The qsort() function sorts an array of \c nmemb objects, the
     initial member of which is pointed to by \c base.  The size of
     each object is specified by \c size.  The contents of the array
     base are sorted in ascending order according to a comparison
     function pointed to by \c compar, which requires two arguments
     pointing to the objects being compared.

     The comparison function must return an integer less than, equal
     to, or greater than zero if the first argument is considered to
     be respectively less than, equal to, or greater than the second.
*/
extern void qsort(void *__base, size_t __nmemb, size_t __size,
		  __compar_fn_t __compar);

/**
    The strtol() function converts the string in \c nptr to a long
    value.  The conversion is done according to the given base, which
    must be between 2 and 36 inclusive, or be the special value 0.

    The string may begin with an arbitrary amount of white space (as
    determined by isspace()) followed by a single optional \c '+' or \c '-'
    sign.  If \c base is zero or 16, the string may then include a
    \c "0x" prefix, and the number will be read in base 16; otherwise,
    a zero base is taken as 10 (decimal) unless the next character is
    \c '0', in which case it is taken as 8 (octal).

    The remainder of the string is converted to a long value in the
    obvious manner, stopping at the first character which is not a
    valid digit in the given base.  (In bases above 10, the letter \c 'A'
    in either upper or lower case represents 10, \c 'B' represents 11,
    and so forth, with \c 'Z' representing 35.)

    If \c endptr is not NULL, strtol() stores the address of the first
    invalid character in \c *endptr.  If there were no digits at all,
    however, strtol() stores the original value of \c nptr in \c
    *endptr.  (Thus, if \c *nptr is not \c '\\0' but \c **endptr is \c '\\0'
    on return, the entire string was valid.)

    The strtol() function returns the result of the conversion, unless
    the value would underflow or overflow.  If no conversion could be
    performed, 0 is returned.  If an overflow or underflow occurs, \c
    errno is set to \ref avr_errno "ERANGE" and the function return value
    is clamped to \c LONG_MIN or \c LONG_MAX, respectively.
*/
extern long strtol(const char *__nptr, char **__endptr, int __base);

/**
    The strtoul() function converts the string in \c nptr to an
    unsigned long value.  The conversion is done according to the
    given base, which must be between 2 and 36 inclusive, or be the
    special value 0.

    The string may begin with an arbitrary amount of white space (as
    determined by isspace()) followed by a single optional \c '+' or \c '-'
    sign.  If \c base is zero or 16, the string may then include a
    \c "0x" prefix, and the number will be read in base 16; otherwise,
    a zero base is taken as 10 (decimal) unless the next character is
    \c '0', in which case it is taken as 8 (octal).

    The remainder of the string is converted to an unsigned long value
    in the obvious manner, stopping at the first character which is
    not a valid digit in the given base.  (In bases above 10, the
    letter \c 'A' in either upper or lower case represents 10, \c 'B'
    represents 11, and so forth, with \c 'Z' representing 35.)

    If \c endptr is not NULL, strtoul() stores the address of the first
    invalid character in \c *endptr.  If there were no digits at all,
    however, strtoul() stores the original value of \c nptr in \c
    *endptr.  (Thus, if \c *nptr is not \c '\\0' but \c **endptr is \c '\\0'
    on return, the entire string was valid.)

    The strtoul() function return either the result of the conversion
    or, if there was a leading minus sign, the negation of the result
    of the conversion, unless the original (non-negated) value would
    overflow; in the latter case, strtoul() returns ULONG_MAX, and \c
    errno is set to \ref avr_errno "ERANGE".  If no conversion could 
    be performed, 0 is returned.
*/
extern unsigned long strtoul(const char *__nptr, char **__endptr, int __base);

/**
    The atol() function converts the initial portion of the string
    pointed to by \c nptr to long integer representation.

    It is equivalent to:

           \code strtol(nptr, (char **)NULL, 10); \endcode
*/
extern __inline__ long atol(const char *__nptr) __ATTR_PURE__;
extern __inline__ long
atol(const char *__nptr)
{
	return strtol(__nptr, (char **) 0, 10);
}

/**
    The atoi() function converts the initial portion of the string
    pointed to by \c nptr to integer representation.

    It is equivalent to:

           \code (int)strtol(nptr, (char **)NULL, 10); \endcode
*/
#ifdef DOXYGEN
extern __inline__ int atoi(const char *__nptr) __ATTR_PURE__;
extern __inline__ int
atoi(const char *__nptr)
{
	return (int) atol(__nptr);
}
#else
/* optimized asm version, much smaller if strtol() not used elsewhere */
extern int atoi(const char *) __ATTR_PURE__;
#endif

/**
   The exit() function terminates the application.  Since there is no
   environment to return to, \c status is ignored, and code execution
   will eventually reach an infinite loop, thereby effectively halting
   all code processing.

   In a C++ context, global destructors will be called before halting
   execution.
*/
extern void exit(int __status) __ATTR_NORETURN__;

/**
   The malloc() function allocates \c size bytes of memory.
   If malloc() fails, a NULL pointer is returned.

   Note that malloc() does \e not initialize the returned memory to
   zero bytes.

   See the chapter about \ref malloc "malloc() usage" for implementation
   details.
*/
extern void *malloc(size_t __size) __ATTR_MALLOC__;

/**
   The free() function causes the allocated memory referenced by \c
   ptr to be made available for future allocations.  If \c ptr is
   NULL, no action occurs.
*/
extern void free(void *__ptr);

/**
   \c malloc() \ref malloc_tunables "tunable".
*/
extern size_t __malloc_margin;

/**
   \c malloc() \ref malloc_tunables "tunable".
*/
extern char *__malloc_heap_start;