NAME

binalloc, bingrow, binfree − grouped memory allocation

SYNOPSIS

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

typedef struct Bin Bin;

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

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

voidbinfree(Bin ∗∗bp);

DESCRIPTION

These routines provide simple grouped memory allocation and deallocation.  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 otherwise.  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. 

Plan 9  —  March 19, 2001