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89 lines
3.3 KiB
Plaintext
89 lines
3.3 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "REALLOC" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" realloc
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.SH NAME
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realloc \- memory reallocator
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.SH SYNOPSIS
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.LP
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\fB#include <stdlib.h>
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.br
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.sp
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void *realloc(void *\fP\fIptr\fP\fB, size_t\fP \fIsize\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The \fIrealloc\fP() function shall change the size of the memory object
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pointed to by \fIptr\fP to the size specified by
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\fIsize\fP. The contents of the object shall remain unchanged up to
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the lesser of the new and old sizes. If the new size of the
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memory object would require movement of the object, the space for
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the previous instantiation of the object is freed. If the new
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size is larger, the contents of the newly allocated portion of the
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object are unspecified. If \fIsize\fP is 0 and \fIptr\fP is
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not a null pointer, the object pointed to is freed. If the space cannot
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be allocated, the object shall remain unchanged.
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.LP
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If \fIptr\fP is a null pointer, \fIrealloc\fP() shall be equivalent
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to \fImalloc\fP()
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for the specified size.
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.LP
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If \fIptr\fP does not match a pointer returned earlier by \fIcalloc\fP(),
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\fImalloc\fP(), or \fIrealloc\fP() or if the space has previously
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been deallocated by a call to \fIfree\fP() or \fIrealloc\fP(), the
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behavior is undefined.
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.LP
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The order and contiguity of storage allocated by successive calls
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to \fIrealloc\fP() is unspecified. The pointer returned if
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the allocation succeeds shall be suitably aligned so that it may be
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assigned to a pointer to any type of object and then used to
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access such an object in the space allocated (until the space is explicitly
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freed or reallocated). Each such allocation shall yield
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a pointer to an object disjoint from any other object. The pointer
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returned shall point to the start (lowest byte address) of the
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allocated space. If the space cannot be allocated, a null pointer
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shall be returned.
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.SH RETURN VALUE
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.LP
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Upon successful completion with a size not equal to 0, \fIrealloc\fP()
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shall return a pointer to the (possibly moved) allocated
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space. If \fIsize\fP is 0, either a null pointer or a unique pointer
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that can be successfully passed to \fIfree\fP() shall be returned.
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If there is not enough available memory, \fIrealloc\fP() shall
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return a null pointer \ and set \fIerrno\fP to [ENOMEM].
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.SH ERRORS
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.LP
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The \fIrealloc\fP() function shall fail if:
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.TP 7
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.B ENOMEM
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Insufficient memory is available.
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.sp
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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None.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIcalloc\fP() , \fIfree\fP() , \fImalloc\fP() ,
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the Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<stdlib.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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