NAME

alloca —

memory allocator

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <stdlib.h>

void *
alloca(size_t size);

DESCRIPTION

The alloca() function allocates size bytes of space in the stack frame of the caller. This temporary space is automatically freed on return.

RETURN VALUES

The alloca() function returns a pointer to the beginning of the allocated space.

HISTORY

The alloca() function appeared in Version 32V AT&T UNIX.

BUGS

The alloca() function is machine and compiler dependent; its use is discouraged.

The alloca() function is slightly unsafe because it cannot ensure that the pointer returned points to a valid and usable block of memory. The allocation made may exceed the bounds of the stack, or even go further into other objects in memory, and alloca() cannot determine such an error. Avoid alloca() with large unbounded allocations.