nuttx/mm/umm_heap
Petro Karashchenko 5a298e8685 mm: memory allocations return valid pointer when request 0 size
This change introduce 2 items:
1. If the size of the space requested is 0, the behavior is implementation-defined:
   either a null pointer shall be returned, or the behavior shall be as if the size
   were some non-zero value, except that the behavior is undefined if the returned
   pointer is used to access an object.

   Change the behavior to be similar to Linux and Android and allocates an object
   of a minimum size instead of returning null pointer.

   https://pubs.opengroup.org/onlinepubs/9699919799/functions/malloc.html
   https://pubs.opengroup.org/onlinepubs/9699919799/functions/calloc.html
   https://pubs.opengroup.org/onlinepubs/9699919799/functions/realloc.html

2. The description of realloc() has been modified from previous versions of this
   standard to align with the ISO/IEC 9899:1999 standard. Previous versions explicitly
   permitted a call to realloc (p, 0) to free the space pointed to by p and return
   a null pointer. While this behavior could be interpreted as permitted by this
   version of the standard, the C language committee have indicated that this
   interpretation is incorrect. Applications should assume that if realloc() returns
   a null pointer, the space pointed to by p has not been freed. Since this could lead
   to double-frees, implementations should also set errno if a null pointer actually
   indicates a failure, and applications should only free the space if errno was changed.

   Do not free memory of zero-length reallocation is requested

   https://pubs.opengroup.org/onlinepubs/9699919799/functions/realloc.html

Co-authored-by: fangxinyong <fangxinyong@xiaomi.com>
Signed-off-by: Petro Karashchenko <petro.karashchenko@gmail.com>
2023-05-02 18:29:29 -06:00
..
Make.defs mm: add kmm/umm_memdump 2022-10-29 11:35:27 +08:00
umm_addregion.c
umm_brkaddr.c
umm_calloc.c mm: memory allocations return valid pointer when request 0 size 2023-05-02 18:29:29 -06:00
umm_checkcorruption.c
umm_extend.c
umm_free.c
umm_globals.c fix #if condition of g_mmheap for BUILD_KERNEL. 2022-02-19 19:33:15 +08:00
umm_heap.h
umm_heapmember.c
umm_initialize.c mm: Enable a dedicated kernel heap on BUILD_FLAT via MM_KERNEL_HEAP 2023-01-17 10:30:00 +08:00
umm_mallinfo.c adjust the contents of memdump and meminfo 2023-01-17 16:48:30 +08:00
umm_malloc_size.c mm:add heap args to mm_malloc_size 2023-01-17 21:57:37 +08:00
umm_malloc.c
umm_memalign.c mm: memory allocations return valid pointer when request 0 size 2023-05-02 18:29:29 -06:00
umm_memdump.c mm: add kmm/umm_memdump 2022-10-29 11:35:27 +08:00
umm_realloc.c mm: memory allocations return valid pointer when request 0 size 2023-05-02 18:29:29 -06:00
umm_sbrk.c
umm_zalloc.c mm: memory allocations return valid pointer when request 0 size 2023-05-02 18:29:29 -06:00