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1 | .\" -*-nroff-*- |
| 2 | .TH arena 3 "3 June 2000" mLib |
| 3 | .SH "NAME" |
| 4 | arena \- control of memory allocation |
| 5 | .\" @arena_global |
| 6 | .\" @arena_stdlib |
| 7 | .\" @arena_fakemalloc |
| 8 | .\" @a_alloc |
| 9 | .\" @a_realloc |
| 10 | .\" @a_free |
| 11 | .\" @A_ALLOC |
| 12 | .\" @A_REALLOC |
| 13 | .\" @A_FREE |
| 14 | .SH "SYNOPSIS" |
| 15 | .nf |
| 16 | .B "#include <mLib/arena.h>" |
| 17 | |
| 18 | .BI "arena *arena_global;" |
| 19 | .BI "arena arena_stdlib;" |
| 20 | |
| 21 | .BI "void *arena_fakerealloc(arena *" a ", void *" p ", size_t " sz ); |
| 22 | |
| 23 | .BI "void *a_alloc(arena *" a ", size_t " sz ); |
| 24 | .BI "void *a_realloc(arena *" a ", void *" p ", size_t " sz ); |
| 25 | .BI "void a_free(arena *" a ); |
| 26 | |
| 27 | .BI "void *A_ALLOC(arena *" a ", size_t " sz ); |
| 28 | .BI "void *A_REALLOC(arena *" a ", void *" p ", size_t " sz ); |
| 29 | .BI "void A_FREE(arena *" a ); |
| 30 | .fi |
| 31 | .SH "DESCRIPTION" |
| 32 | An |
| 33 | .I arena |
| 34 | is a place from which blocks of memory may be allocated and freed. The |
| 35 | basic |
| 36 | .B mLib |
| 37 | library provides a single standard arena, |
| 38 | .BR arena_stdlib , |
| 39 | which uses the usual |
| 40 | .BR malloc (3) |
| 41 | and |
| 42 | .BR free (3) |
| 43 | calls. The global variable |
| 44 | .B arena_global |
| 45 | is a pointer to a `current' arena, which is a good choice to use if |
| 46 | you can't think of anything better. |
| 47 | .PP |
| 48 | The macros |
| 49 | .BR A_ALLOC , |
| 50 | .B A_REALLOC |
| 51 | and |
| 52 | .B A_FREE |
| 53 | behave like the standard C functions |
| 54 | .BR malloc (3), |
| 55 | .BR realloc (3) |
| 56 | and |
| 57 | .BR free (3), |
| 58 | allocating, resizing and releasing blocks from a given arena. There are |
| 59 | function-call equivalents with lower-case names too. For a more |
| 60 | convenient interface to memory allocation, see |
| 61 | .BR alloc (3). |
| 62 | .PP |
| 63 | .SS "Defining new arenas" |
| 64 | An |
| 65 | .B arena |
| 66 | is a structure containing a single member, |
| 67 | .BR ops , |
| 68 | which is a pointer to a structure of type |
| 69 | .BR arena_ops . |
| 70 | The |
| 71 | .B arena |
| 72 | structure may be followed in memory by data which is used by the arena's |
| 73 | manager to maintain its state. |
| 74 | .PP |
| 75 | The |
| 76 | .B arena_ops |
| 77 | table contains function pointers which are called to perform various |
| 78 | memory allocation tasks: |
| 79 | .TP |
| 80 | .BI "void *(*" alloc ")(arena *" a ", size_t " sz ); |
| 81 | Allocates a block of memory, of at least |
| 82 | .I sz |
| 83 | bytes in size, appropriately aligned, and returns its address. |
| 84 | .TP |
| 85 | .BI "void *(*" realloc ")(arena *" a ", void *" p ", size_t " sz ); |
| 86 | Resizes the block pointed to by |
| 87 | .IR p , |
| 88 | so that it is at least |
| 89 | .I sz |
| 90 | bytes long. You can use |
| 91 | .B arena_fakerealloc |
| 92 | here, to fake resizing by allocating, copying and freeing, if your arena |
| 93 | doesn't make doing something more efficient easy. |
| 94 | .TP |
| 95 | .BI "void (*" free ")(arena *" a ", void *" p ); |
| 96 | Frees the block pointed to by |
| 97 | .IR p . |
| 98 | .TP |
| 99 | .BI "void (*" purge ")(arena *" a ); |
| 100 | Frees all blocks in the arena. Used when the arena is being destroyed. |
| 101 | .PP |
| 102 | The behaviour of the |
| 103 | .IR alloc , |
| 104 | .I realloc |
| 105 | and |
| 106 | .I free |
| 107 | calls with respect to null pointers and zero-sized blocks is as |
| 108 | specified by the ANSI C standard. |
| 109 | .SH "SEE ALSO" |
| 110 | .BR alloc (3), |
| 111 | .BR mLib (3). |
| 112 | .SH AUTHOR |
| 113 | Mark Wooding, <mdw@nsict.org> |
~mdw / mLib / blame