1.\" Copyright (c) 1980, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" @(#)malloc.3 6.7 (Berkeley) 6/29/91 37.\" 38.Dd June 29, 1991 39.Dt MALLOC 3 40.Os BSD 4 41.Sh NAME 42.Nm malloc , 43.Nd general memory allocation function 44.Sh SYNOPSIS 45.Fd #include <stdlib.h> 46.Ft void * 47.Fn malloc "size_t size" 48.Sh DESCRIPTION 49The 50.Fn malloc 51function allocates uninitialized space for an object whose 52size is specified by 53.Fa size . 54The 55.Fn malloc 56function maintains multiple lists of free blocks according to size, allocating 57space from the appropriate list. 58.Pp 59The allocated space is 60suitably aligned (after possible pointer 61coercion) for storage of any type of object. If the space is of 62.Em pagesize 63or larger, the memory returned will be page-aligned. 64.Sh RETURN VALUES 65The 66.Fn malloc 67function returns 68a pointer to the allocated space if successful; otherwise 69a null pointer is returned. 70.Sh SEE ALSO 71.Xr brk 2 , 72.Xr pagesize 2 , 73.Xr free 3 , 74.Xr calloc 3 , 75.Xr alloca 3 , 76.Xr realloc 3 , 77.Xr memory 3 78.Sh STANDARDS 79The 80.Fn malloc 81function conforms to 82.St -ansiC . 83.Sh BUGS 84The current implementation of 85.Xr malloc 86does not always fail gracefully when system 87memory limits are approached. 88It may fail to allocate memory when larger free blocks could be broken 89up, or when limits are exceeded because the size is rounded up. 90It is optimized for sizes that are powers of two. 91