NAME

       hal_malloc - Allocate space in the HAL shared memory area

SYNTAX

               void *hal_malloc(long int size)

ARGUMENTS

       size   Gives the size, in bytes, of the block.

DESCRIPTION

       hal_malloc  allocates  a  block of memory from the main HAL shared memory area.  It should be used by all
       components to allocate memory for HAL pins and parameters.  It allocates  `size'  bytes,  and  returns  a
       pointer  to the allocated space, or NULL (0) on error.  The returned pointer will be properly aligned for
       any type HAL supports.  A component should allocate during initialization all the memory it needs.

       The allocator is very simple, and there is no `free'.  The entire HAL shared memory area  is  freed  when
       the  last component calls hal_exit.  This means that if you continuously install and remove one component
       while other components are present, you eventually will fill up the shared memory  and  an  install  will
       fail.  Removing all components completely clears memory and you start fresh.

RETURN VALUE

       A  pointer to the allocated space, which is properly aligned for any variable HAL supports.  Returns NULL
       on error.

LinuxCNC Documentation                             2006-10-12                                   hal_malloc(3hal)