Subversion Repositories or1k

/* VxWorks provides its own version of malloc, and we can't use this

   one because VxWorks does not provide sbrk.  So we have a hook to

   not compile this code.  */

/* The routines here are simple cover fns to the routines that do the real

   work (the reentrant versions).  */

/* FIXME: Does the warning below (see WARNINGS) about non-reentrancy still

   apply?  A first guess would be "no", but how about reentrancy in the *same*

   thread?  */

#ifdef MALLOC_PROVIDED

int _dummy_malloc = 1;

#else

/*

FUNCTION

<<malloc>>, <<realloc>>, <<free>>---manage memory

INDEX

        malloc

INDEX

        realloc

INDEX

        free

INDEX

        memalign

INDEX

        malloc_usable_size

INDEX

        _malloc_r

INDEX

        _realloc_r

INDEX

        _free_r

INDEX

        _memalign_r

INDEX

        _malloc_usable_size_r

ANSI_SYNOPSIS

        #include <stdlib.h>

        void *malloc(size_t <[nbytes]>);

        void *realloc(void *<[aptr]>, size_t <[nbytes]>);

        void free(void *<[aptr]>);

        void *memalign(size_t <[align]>, size_t <[nbytes]>);

        size_t malloc_usable_size(void *<[aptr]>);

        void *_malloc_r(void *<[reent]>, size_t <[nbytes]>);

        void *_realloc_r(void *<[reent]>,

                         void *<[aptr]>, size_t <[nbytes]>);

        void _free_r(void *<[reent]>, void *<[aptr]>);

        void *_memalign_r(void *<[reent]>,

                          size_t <[align]>, size_t <[nbytes]>);

        size_t _malloc_usable_size_r(void *<[reent]>, void *<[aptr]>);

TRAD_SYNOPSIS

        #include <stdlib.h>

        char *malloc(<[nbytes]>)

        size_t <[nbytes]>;

        char *realloc(<[aptr]>, <[nbytes]>)

        char *<[aptr]>;

        size_t <[nbytes]>;

        void free(<[aptr]>)

        char *<[aptr]>;

        char *memalign(<[align]>, <[nbytes]>)

        size_t <[align]>;

        size_t <[nbytes]>;

        size_t malloc_usable_size(<[aptr]>)

        char *<[aptr]>;

        char *_malloc_r(<[reent]>,<[nbytes]>)

        char *<[reent]>;

        size_t <[nbytes]>;

        char *_realloc_r(<[reent]>, <[aptr]>, <[nbytes]>)

        char *<[reent]>;

        char *<[aptr]>;

        size_t <[nbytes]>;

        void _free_r(<[reent]>, <[aptr]>)

        char *<[reent]>;

        char *<[aptr]>;

        char *_memalign_r(<[reent]>, <[align]>, <[nbytes]>)

        char *<[reent]>;

        size_t <[align]>;

        size_t <[nbytes]>;

        size_t malloc_usable_size(<[reent]>, <[aptr]>)

        char *<[reent]>;

        char *<[aptr]>;

DESCRIPTION

These functions manage a pool of system memory.

Use <<malloc>> to request allocation of an object with at least

<[nbytes]> bytes of storage available.  If the space is available,

<<malloc>> returns a pointer to a newly allocated block as its result.

If you already have a block of storage allocated by <<malloc>>, but

you no longer need all the space allocated to it, you can make it

smaller by calling <<realloc>> with both the object pointer and the

new desired size as arguments.  <<realloc>> guarantees that the

contents of the smaller object match the beginning of the original object.

Similarly, if you need more space for an object, use <<realloc>> to

request the larger size; again, <<realloc>> guarantees that the

beginning of the new, larger object matches the contents of the

original object.

When you no longer need an object originally allocated by <<malloc>>

or <<realloc>> (or the related function <<calloc>>), return it to the

memory storage pool by calling <<free>> with the address of the object

as the argument.  You can also use <<realloc>> for this purpose by

calling it with <<0>> as the <[nbytes]> argument.

The <<memalign>> function returns a block of size <[nbytes]> aligned

to a <[align]> boundary.  The <[align]> argument must be a power of

two.

The <<malloc_usable_size>> function takes a pointer to a block

allocated by <<malloc>>.  It returns the amount of space that is

available in the block.  This may or may not be more than the size

requested from <<malloc>>, due to alignment or minimum size

constraints.

The alternate functions <<_malloc_r>>, <<_realloc_r>>, <<_free_r>>,

<<_memalign_r>>, and <<_malloc_usable_size_r>> are reentrant versions.

The extra argument <[reent]> is a pointer to a reentrancy structure.

If you have multiple threads of execution which may call any of these

routines, or if any of these routines may be called reentrantly, then

you must provide implementations of the <<__malloc_lock>> and

<<__malloc_unlock>> functions for your system.  See the documentation

for those functions.

These functions operate by calling the function <<_sbrk_r>> or

<<sbrk>>, which allocates space.  You may need to provide one of these

functions for your system.  <<_sbrk_r>> is called with a positive

value to allocate more space, and with a negative value to release

previously allocated space if it is no longer required.

@xref{Stubs}.

RETURNS

<<malloc>> returns a pointer to the newly allocated space, if

successful; otherwise it returns <<NULL>>.  If your application needs

to generate empty objects, you may use <<malloc(0)>> for this purpose.

<<realloc>> returns a pointer to the new block of memory, or <<NULL>>

if a new block could not be allocated.  <<NULL>> is also the result

when you use `<<realloc(<[aptr]>,0)>>' (which has the same effect as

`<<free(<[aptr]>)>>').  You should always check the result of

<<realloc>>; successful reallocation is not guaranteed even when

you request a smaller object.

<<free>> does not return a result.

<<memalign>> returns a pointer to the newly allocated space.

<<malloc_usable_size>> returns the usable size.

PORTABILITY

<<malloc>>, <<realloc>>, and <<free>> are specified by the ANSI C

standard, but other conforming implementations of <<malloc>> may

behave differently when <[nbytes]> is zero.

<<memalign>> is part of SVR4.

<<malloc_usable_size>> is not portable.

Supporting OS subroutines required: <<sbrk>>.  */

#include <_ansi.h>

#include <reent.h>

#include <stdlib.h>

#include <malloc.h>

#ifndef _REENT_ONLY

_PTR

_DEFUN (malloc, (nbytes),

        size_t nbytes)          /* get a block */

{

  return _malloc_r (_REENT, nbytes);

}

void

_DEFUN (free, (aptr),

        _PTR aptr)

{

  _free_r (_REENT, aptr);

}

#endif

#endif /* ! defined (MALLOC_PROVIDED) */