1.\" $NetBSD: malloc.3,v 1.8 1998/02/05 18:50:03 perry Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" the American National Standards Committee X3, on Information 8.\" Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. All advertising materials mentioning features or use of this software 19.\" must display the following acknowledgement: 20.\" This product includes software developed by the University of 21.\" California, Berkeley and its contributors. 22.\" 4. Neither the name of the University nor the names of its contributors 23.\" may be used to endorse or promote products derived from this software 24.\" without specific prior written permission. 25.\" 26.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36.\" SUCH DAMAGE. 37.\" 38.\" from: @(#)malloc.3 8.1 (Berkeley) 6/4/93 39.\" 40.Dd June 4, 1993 41.Dt MALLOC 3 42.Os BSD 4 43.Sh NAME 44.Nm malloc 45.Nd general memory allocation function 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.Fd #include <stdlib.h> 50.Ft void * 51.Fn malloc "size_t size" 52.Sh DESCRIPTION 53The 54.Fn malloc 55function allocates uninitialized space for an object whose 56size is specified by 57.Fa size . 58The 59.Fn malloc 60function maintains multiple lists of free blocks according to size, allocating 61space from the appropriate list. 62.Pp 63The allocated space is 64suitably aligned (after possible pointer 65coercion) for storage of any type of object. If the space is of 66.Em pagesize 67or larger, the memory returned will be page-aligned. 68.Sh RETURN VALUES 69The 70.Fn malloc 71function returns 72a pointer to the allocated space if successful; otherwise 73a null pointer is returned. 74.Sh SEE ALSO 75.Xr brk 2 , 76.Xr alloca 3 , 77.Xr calloc 3 , 78.Xr free 3 , 79.Xr getpagesize 3 , 80.Xr memory 3 , 81.Xr realloc 3 82.Sh STANDARDS 83The 84.Fn malloc 85function conforms to 86.St -ansiC . 87.Sh BUGS 88The current implementation of 89.Fn malloc 90does not always fail gracefully when system 91memory limits are approached. 92It may fail to allocate memory when larger free blocks could be broken 93up, or when limits are exceeded because the size is rounded up. 94It is optimized for sizes that are powers of two. 95