Standard C++ Library Reference ISO/IEC (VERSION3)

NULL
#define NULL <either 0, 0L, or (void *)0> [0 in C++]
The macro yields a null pointer constant that is usable as an address constant expression.
qsort
extern "C++"
void qsort(void *base, size_t nelem, size_t size,
int (*cmp)(const void *e1, const void *e2));
[C++ only]
extern "C" [C++ only]
void qsort(void *base, size_t nelem, size_t size,
int (*cmp)(const void *e1, const void *e2));
The function sorts, in place, an array consisting of nelem elements, each of size bytes,
beginning with the element whose address is base. It calls the comparison function whose
address is cmp to compare pairs of elements. The comparison function must return a negative
value if e1 is less than e2, zero if the two are equal, or a positive value if e1 is greater than e2.
Two array elements that are equal can appear in the sorted array in either order.
rand
int rand(void);
The function computes a pseudo-random number x based on a seed value stored in an internal
static-duration object, alters the stored seed value, and returns x. x is in the interval [0,
RAND_MAX].
RAND_MAX
#define RAND_MAX <integer constant expression >= 32,767>
The macro yields the maximum value returned by rand.
realloc
void *realloc(void *ptr, size_t size);
The function allocates an object of size size, possibly obtaining initial stored values from the
object whose address is ptr. It returns the address of the new object if successful; otherwise, it
returns a null pointer. You can safely convert the return value to an object pointer of any type