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BIN(2)                        System Calls Manual                       BIN(2)



NAME
       binalloc, bingrow, binfree - grouped memory allocation

SYNOPSIS
       #include <u.h>
       #include <libc.h>
       #include <bin.h>

       typedef struct BinBin;

       void  *binalloc(Bin **bp, ulong size, int clr);

       void  *bingrow(Bin **bp, void *op, ulong osize,
             ulong size, int clr);

       void  binfree(Bin **bp);

DESCRIPTION
       These  routines  provide simple grouped memory allocation and dealloca‐
       tion.  Items allocated with binalloc are added to the Bin pointed to by
       bp.  All items in a bin may be freed with one call to binfree; there is
       no way to free a single item.

       Binalloc returns a pointer to a new block of at least size bytes.   The
       block  is  suitably  aligned for storage of any type of object.  No two
       active pointers from binalloc will  have  the  same  value.   The  call
       binalloc(0)  returns  a valid pointer rather than null.  If clr is non-
       zero, the allocated memory is set to 0;  otherwise,  the  contents  are
       undefined.

       Bingrow  is  used  to  extend the size of a block of memory returned by
       binalloc.  Bp must point to the same bin group  used  to  allocate  the
       original  block,  and  osize  must be the last size used to allocate or
       grow the block.  A pointer to  a  block  of  at  least  size  bytes  is
       returned,  with the same contents in the first osize locations.  If clr
       is non-zero, the remaining bytes are set to 0, and are undefined other‐
       wise.   If  op  is nil, it and osize are ignored, and the result is the
       same as calling binalloc.

       Binalloc and bingrow allocate large chunks of  memory  using  malloc(2)
       and  return  pieces of these chunks.  The chunks are free'd upon a call
       to binfree.

SOURCE
       /sys/src/libbin

SEE ALSO
       malloc(2)

DIAGNOSTICS
       binalloc and bingrow return 0 if there is no available memory.



                                                                        BIN(2)