copymsg(9r) [osf1 man page]

copymsg(9r)															       copymsg(9r)

NAME

       copymsg - STREAMS: Copies a message to a new message

SYNOPSIS

       #include <sys/stream.h>

       MBLKP copymsg(
	       MBLKP message_block );

ARGUMENTS

       Specifies  a  pointer  to  the  message	block from which copymsg copies the data. (Actually, copymsg calls the copyb interface to copy the
       data.) The typedef MBLKP is an alternate name for typedef struct msgb *.

DESCRIPTION

       The copymsg interface: Forms a new message by allocating new message blocks Copies (by calling the copyb interface)  the  contents  of  the
       message referred to by the message_block argument Returns a pointer to the new message block.

RETURN VALUES

       Upon  successful  completion,  the  copymsg interface returns a pointer to the newly allocated message block that contains the copied data.
       This newly allocated message block is of type struct msgb *. The msgb data structure is defined in the /usr/sys/include/sys/stream.h file.

       Otherwise, copymsg returns a NULL pointer.

SEE ALSO

       Kernel Interfaces: allocb(9r), copyb(9r)

       Programmer's Guide: STREAMS

																       copymsg(9r)

copymsg(9F)						   Kernel Functions for Drivers 					       copymsg(9F)

NAME

       copymsg - copy a message

SYNOPSIS

       #include <sys/stream.h>

       mblk_t *copymsg(mblk_t *mp);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI).

PARAMETERS

       mp	Pointer to the message to be copied.

DESCRIPTION

       copymsg()  forms  a  new  message  by  allocating  new message blocks, and copying the contents of the message referred to by mp (using the
       copyb(9F) function). It returns a pointer to the new message.

RETURN VALUES

       If the copy is successful, copymsg() returns a pointer to the new message.  Otherwise, it returns a NULL pointer.

CONTEXT

       copymsg() can be called from user or interrupt context.

EXAMPLES

       Example 1: : Using copymsg

       The routine lctouc() converts all the lowercase ASCII characters in the message to uppercase. If the reference count is	greater  than  one
       (line  8),  then  the  message  is shared, and must be copied before changing the contents of the data buffer. If the call to the copymsg()
       function fails (line 9), return NULL (line 10), otherwise, free the original message (line 11). If the reference count was equal to 1,  the
       message can be modified. For each character (line 16) in each message block (line 15), if it is a lowercase letter, convert it to an upper-
       case letter (line 18). A pointer to the converted message is returned (line 21).

	1 mblk_t *lctouc(mp)
	2    mblk_t *mp;
	3 {
	4    mblk_t *cmp;
	5    mblk_t *tmp;
	6    unsigned char *cp;
	7
	8    if (mp->b_datap->db_ref > 1) {
	9	     if ((cmp = copymsg(mp)) == NULL)
       10		      return (NULL);
       11	     freemsg(mp);
       12    } else {
       13	     cmp = mp;
       14    }
       15    for (tmp = cmp; tmp; tmp = tmp->b_cont) {
       16	     for (cp = tmp->b_rptr; cp < tmp->b_wptr; cp++) {
       17		     if ((*cp <= 'z') && (*cp >= 'a'))
       18			      *cp -= 0x20;
       19	     }
       20    }
       21    return(cmp);
       22 }

SEE ALSO

       allocb(9F), copyb(9F), msgb(9S)

       Writing Device Drivers

	STREAMS Programming Guide

SunOS 5.10							    27 Jun 1995 						       copymsg(9F)