REALLOC

Section: C Library Functions (3)
Index Return to Main Contents

BSD mandoc

NAME

realloc - reallocation of memory function

SYNOPSIS

Fd #include <stdlib.h> Ft void * Fn realloc void *ptr size_t size

DESCRIPTION

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

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

STANDARDS

The Fn realloc function conforms to St -ansiC .