realloc(3) - NetBSD Manual Pages

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REALLOC(3)                NetBSD Programmer's Manual                REALLOC(3)


NAME

     realloc - reallocation of memory function


SYNOPSIS

     #include <stdlib.h>

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


DESCRIPTION

     The realloc() function changes the size of the object pointed to by ptr
     to the size specified by size. The contents of the object are unchanged
     up to the lesser of the new and old sizes.  If the new size is larger,
     the value of the newly allocated portion of the object is indeterminate.
     If ptr is a null pointer, the realloc() function behaves like the malloc(3)
      function for the specified size.  Otherwise, if ptr does not match
     a pointer earlier returned by the calloc(3),  malloc(3),  or realloc()
     function, or if the space has been deallocated by a call to the free or
     realloc() function, unpredictable and usually detrimental behavior will
     occur.  If the space cannot be allocated, the object pointed to by ptr is
     unchanged.  If size is zero and ptr is not a null pointer, the object it
     points to is freed.

     The realloc() function returns either a null pointer or a pointer to the
     possibly moved allocated space.


SEE ALSO

     alloca(3),  calloc(3),  free(3),  malloc(3),


STANDARDS

     The realloc() function conforms to ANSI X3.159-1989 (``ANSI C'').

4.4BSD                            May 2, 1991                                1