STREAMS-UX Programmer's Guide (February 2007)

STREAMS Utilities Supported by HP-UX

Appendix B

175

NAME

freeb () – Deallocates a message block.

SYNOPSIS

#include <sys/stream.h>

void freeb (mblk_t *mp);

PARAMETERS

Pointer to the message block to be deallocated.

DESCRIPTION

freeb() deallocates a message block, and if the db_ref count of the datab structure it is pointing to is

greater than 1, it decrements the db_ref count by 1 and deallocates only the message block descriptor. If the

db_ref count of the data block is 1, freeb() deallocates the message block descriptor and the data buffer.

If the message block was created via the esballoc() call, and if db_ref is 1, freeb() notifies the driver by

invoking the free_func as pointed in the free_rtn structure. It waits for the driver to complete the

free_rtn operation, and then proceeds to release the message block and data block.

RETURN VALUES

None

CONSTRAINTS

freeb() can be called from thread or interrupt context. Only spinlocks of STREAMS/UX user lock order can

be held across this call.