MALLOC(P) POSIX Programmer's Manual MALLOC(P)NAMEmalloc - a memory allocator
SYNOPSIS
#include <stdlib.h>
void *malloc(size_t size);
DESCRIPTION
The malloc() function shall allocate unused space for an object whose
size in bytes is specified by size and whose value is unspecified.
The order and contiguity of storage allocated by successive calls to
malloc() is unspecified. The pointer returned if the allocation suc‐
ceeds shall be suitably aligned so that it may be assigned to a pointer
to any type of object and then used to access such an object in the
space allocated (until the space is explicitly freed or reallocated).
Each such allocation shall yield a pointer to an object disjoint from
any other object. The pointer returned points to the start (lowest byte
address) of the allocated space. If the space cannot be allocated, a
null pointer shall be returned. If the size of the space requested is
0, the behavior is implementation-defined: the value returned shall be
either a null pointer or a unique pointer.
RETURN VALUE
Upon successful completion with size not equal to 0, malloc() shall
return a pointer to the allocated space. If size is 0, either a null
pointer or a unique pointer that can be successfully passed to free()
shall be returned. Otherwise, it shall return a null pointer and set
errno to indicate the error.
ERRORS
The malloc() function shall fail if:
ENOMEM Insufficient storage space is available.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSOcalloc() , free() , realloc() , the Base Definitions volume of
IEEE Std 1003.1-2001, <stdlib.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 MALLOC(P)
