allocb(9r) allocb(9r)
NAME
allocb - STREAMS: Allocates a message block
SYNOPSIS
#include <sys/stream.h>
MBLKP allocb(
int size,
uint pri );
ARGUMENTS
Specifies the number of bytes in the message block. Specifies the priority of the request. You use this argument to determine if the allo-
cation of memory blocks (waits) on the request. If you call the allocb interface at a high priority and it blocks on the request, the sys-
tem could deadlock. Typically, you pass the constant BPRI_WAITOK, which signifies that allocb can block. If allocb cannot block, you should
pass the BPRI_HI constant.
DESCRIPTION
The allocb interface attempts to allocate a STREAMS message block. Buffer allocation fails only when the system is out of memory. If no
buffer is available, you can call the bufcall interface, which helps a module recover from a memory allocation failure.
RETURN VALUES
Upon successful completion, the allocb interface returns a pointer to the allocated message block. This message block is of type struct
msgb *. The msgb data structure is defined in the /usr/sys/include/sys/stream.h file.
If allocb cannot allocate a message block, it returns a NULL pointer.
SEE ALSO
Kernel Routines: bufcall(9r), esballoc(9r), testb(9r)
Programmer's Guide: STREAMS
allocb(9r)
