NAME
alloca, calloc, free, malloc, mmap, realloc – general memory allocation operations
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
void *
alloca(size_t size);
void *
calloc(size_t nelem, size_t elsize);
void
free(void *ptr);
void *
malloc(size_t size);
void *
realloc(void *ptr, size_t size);
#include <sys/mman.h>
void *
mmap(void * addr, size_t len, int prot, int flags, int fildes, off_t off);
DESCRIPTION
These functions allocate and free memory for the calling process. They are described in the individual manual pages.
LEGACY SYNOPSIS
#include <sys/types.h> #include <sys/mman.h>
void *
mmap(void * addr, size_t len, int prot, int flags, int fildes, off_t off);
The include file ⟨sys/types.h⟩ is needed for this function.
COMPATIBILITY
mmap() now returns with errno set to EINVAL in places that historically succeeded. The rules have changed as follows:
-
The flags parameter must specify either MAP_PRIVATE or MAP_SHARED.
-
The size parameter must not be 0.
-
The off parameter must be a multiple of pagesize, as returned by sysconf().
SEE ALSO
mmap(2), alloca(3), calloc(3), free(3), malloc(3), realloc(3), compat(5)
STANDARDS
These functions, with the exception of alloca() and mmap() conform to ISO/IEC 9899:1990 (“ISO C90”).