malloc(3p) [posix man page]

MALLOC(3P)						     POSIX Programmer's Manual							MALLOC(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       malloc -- a memory allocator

SYNOPSIS

       #include <stdlib.h>

       void *malloc(size_t size);

DESCRIPTION

       The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here
       and the ISO C standard is unintentional. This volume of POSIX.1-2008 defers to the ISO C standard.

       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 ALSO

       calloc(), free(), getrlimit(), posix_memalign(), realloc()

       The Base Definitions volume of POSIX.1-2008, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol-
       ogy  --	Portable  Operating  System  Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 Stan-
       dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE
/The Open Group						       2013								MALLOC(3P)

REALLOC(3P)						     POSIX Programmer's Manual						       REALLOC(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       realloc - memory reallocator

SYNOPSIS

       #include <stdlib.h>

       void *realloc(void *ptr, size_t size);

DESCRIPTION

       The realloc() function shall change the size of the memory object pointed to by ptr to the size specified by  size.  The  contents  of  the
       object shall remain unchanged up to the lesser of the new and old sizes. If the new size of the memory object would require movement of the
       object, the space for the previous instantiation of the object is freed. If the new size is larger, the contents  of  the  newly  allocated
       portion	of  the object are unspecified. If size is 0 and ptr is not a null pointer, the object pointed to is freed. If the space cannot be
       allocated, the object shall remain unchanged.

       If ptr is a null pointer, realloc() shall be equivalent to malloc() for the specified size.

       If ptr does not match a pointer returned earlier by calloc(), malloc(), or realloc() or if the space has previously been deallocated  by  a
       call to free() or realloc(), the behavior is undefined.

       The  order and contiguity of storage allocated by successive calls to realloc() 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 shall point to the start (lowest byte address) of the allocated space. If the space cannot be  allo-
       cated, a null pointer shall be returned.

RETURN VALUE

       Upon successful completion with a size not equal to 0, realloc() shall return a pointer to the (possibly moved) allocated space. If size is
       0, either a null pointer or a unique pointer that can be successfully passed to free() shall be returned.  If there is not enough available
       memory, realloc() shall return a null pointer  and set errno to [ENOMEM].

ERRORS

       The realloc() function shall fail if:

       ENOMEM Insufficient memory is available.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       calloc(), free(), malloc(), 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 Technol-
       ogy -- 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							       REALLOC(3P)