pass a pointer-to-pointer, or return a pointer? Post: 302273849

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allocb

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)