Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Real time embedded FreeRTOS mailing list 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem TCP & FAT Training


Heap allocate size ...

Posted by debugasm on March 29, 2016


in my application I use a heap memory with code of "heap4". I have the need to use the "realloc" function to provide a already allocated memory area. I have write a wrapper to this function on "heap4" but I realized now that I do not know the size of the old allocation to copy the old content to the new memory area.

There is a function "mallocusablesize" that returns this value but how implement this routine in "heap_4" ?

You can know the size of a memory block allocated by vPortMalloc ?

Thanks very much.


Heap allocate size ...

Posted by rtel on March 29, 2016

The size of every block is stored in a BlockLink_t structure, in the allocated block itself. See the implementation of vPortFree() for an example of how it is accessed.

Heap allocate size ...

Posted by debugasm on March 29, 2016

I understand, thank you so much.


Heap allocate size ...

Posted by debugasm on March 30, 2016

To be precise:

~~~~ // The block is being returned to the heap - it is no longer allocated. block_size = (pxLink->xBlockSize & ~xBlockAllocatedBit) - xHeapStructSize; ~~~~

Obtain block size allocate by "pvPortMalloc" rounded to "BYTE_ALIGNMENT"


[ Back to the top ]    [ About FreeRTOS ]    [ Sitemap ]    [ ]

Copyright (C) 2004-2010 Richard Barry. Copyright (C) 2010-2016 Real Time Engineers Ltd.
Any and all data, files, source code, html content and documentation included in the FreeRTOSTM distribution or available on this site are the exclusive property of Real Time Engineers Ltd.. See the files license.txt (included in the distribution) and this copyright notice for more information. FreeRTOSTM and FreeRTOS.orgTM are trade marks of Real Time Engineers Ltd.

Latest News:

FreeRTOS V9.0.0 is now available for download.

Free TCP/IP and file system demos for the RTOS

Sponsored Links

⇓ Now With No Code Size Limit! ⇓
⇑ Free Download Without Registering ⇑

FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

Renesas Electronics Gold Alliance RTOS Partner.jpg

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers

Atmel RTOS partner supporting ARM Cortex-M3 and AVR32 microcontrollers

STMicro RTOS partner supporting ARM7, ARM Cortex-M3, ARM Cortex-M4 and ARM Cortex-M0

Xilinx Microblaze and Zynq partner

Silicon Labs low power RTOS partner

Altera RTOS partner for Nios II and Cortex-A9 SoC

Freescale Alliance RTOS Member supporting ARM and ColdFire microcontrollers

Infineon ARM Cortex-M microcontrollers

Texas Instruments MCU Developer Network RTOS partner for ARM and MSP430 microcontrollers

Cypress RTOS partner supporting ARM Cortex-M3

Fujitsu RTOS partner supporting ARM Cortex-M3 and FM3

Microsemi (previously Actel) RTOS partner supporting ARM Cortex-M3

Atollic Partner

IAR Partner

Keil ARM Partner

Embedded Artists