SVR5

bzero(D3)

bzero -- clear memory for a given number of bytes

Synopsis

   #include <sys/types.h>
   #include <sys/ddi.h>
   
   void bzero(caddr_t addr, size_t bytes);

Description

The bzero function clears a contiguous portion of memory by filling the memory with zeros. It chooses the best algorithm based on address alignment and number of bytes to clear.

Arguments

addr: Starting virtual address of memory to be cleared.
bytes: The number of bytes to clear.

Return values

None

Usage

There are no alignment restrictions on addr, and no length restrictions on bytes, other than that the address range specified must be within the kernel address space and must be memory resident. No range checking is done. Since there is no mechanism by which drivers that conform to the rules of the DDI can obtain and use a kernel address that is not memory resident (an address that is paged out), DDI conforming drivers can assume that any address to which they have access is memory resident and therefore a valid argument to bzero( ). An address within user address space is not a valid argument, and specifying such an address may cause the driver to corrupt the system in an unpredictable way.

Context and synchronization

All contexts.

Examples

In a driver close(D2) routine, rather than clear each individual member of its private data structure, the driver could use bzero as shown here:

   bzero(&drv_dat[chan], sizeof(struct drvr_data));

Hardware applicability

All

Version applicability

ddi: 1, 2, 3, 4, 5, 5mp, 6, 6mp, 7, 7mp, 7.1, 7.1mp, 8, 8mp

References

bcopy(D3), clrbuf(D3), kmem_zalloc(D3)