copymsg(9F)

NAME | SYNOPSIS | INTERFACE LEVEL | PARAMETERS | DESCRIPTION | RETURN VALUES | CONTEXT | EXAMPLES | SUMMARY OF TRUSTED SOLARIS CHANGES | SEE ALSO | NOTES

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 is 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 uppercase 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 }

---

SUMMARY OF TRUSTED SOLARIS CHANGES

This routine will assign correct attributes to the message it copies.

SEE ALSO

Trusted Solaris 8 4/01 Reference Manual

copyb(9F)

SunOS 5.8 Reference Manual

allocb(9F), msgb(9S)

Writing Device Drivers

STREAMS Programming Guide

NOTES

These interfaces are uncommitted. Although not expected to do so, they may change between minor Trusted Solaris releases.

SunOS 5.8  Last Revised 27 Jun 1995

NAME | SYNOPSIS | INTERFACE LEVEL | PARAMETERS | DESCRIPTION | RETURN VALUES | CONTEXT | EXAMPLES | SUMMARY OF TRUSTED SOLARIS CHANGES | SEE ALSO | NOTES