10-16-2005
The decision of whether to use malloc or not really depends on you.
If you want to have a program that does not allocate space that it does not need, then you should use malloc to allocate space when you know how much you will need. Also, if you are expecting to allocate a very large array, say of 100000 bytes or something, but it is possible that some cases may have only 500 of those bytes actually used, then you are again better off using malloc to allocate just those many bytes.
Of course, if you are going to use malloc - especially in a loop, remember to use free, or you risk crashing your program.
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1 . Thanks everyone who read the post.
2 . the programe is that :
#include <stdio.h>
#include <string.h>
void do_it(char *p)
{
p = (char *) malloc(100);
(void )strcpy(p,"1234");
}
int main(void)
{
char *p;
do_it(p);
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LEARN ABOUT DEBIAN
net::dns::question
Net::DNS::Question(3pm) User Contributed Perl Documentation Net::DNS::Question(3pm)
NAME
Net::DNS::Question - DNS question class
SYNOPSIS
"use Net::DNS::Question"
DESCRIPTION
A "Net::DNS::Question" object represents a record in the question section of a DNS packet.
METHODS
new
$question = Net::DNS::Question->new("example.com", "MX", "IN");
Creates a question object from the domain, type, and class passed as arguments.
RFC4291 and RFC4632 IP address/prefix notation is supported for queries in in-addr.arpa and ip6.arpa subdomains.
parse
($question, $offset) = Net::DNS::Question->parse($data, $offset);
Parses a question section record at the specified location within a DNS packet. The first argument is a reference to the packet data. The
second argument is the offset within the packet where the question record begins.
Returns a Net::DNS::Question object and the offset of the next location in the packet.
Parsing is aborted if the question object cannot be created (e.g., corrupt or insufficient data).
qname, zname
print "qname = ", $question->qname, "
";
print "zname = ", $question->zname, "
";
Returns the domain name. In dynamic update packets, this field is known as "zname" and refers to the zone name.
qtype, ztype
print "qtype = ", $question->qtype, "
";
print "ztype = ", $question->ztype, "
";
Returns the record type. In dymamic update packets, this field is known as "ztype" and refers to the zone type (must be SOA).
qclass, zclass
print "qclass = ", $question->qclass, "
";
print "zclass = ", $question->zclass, "
";
Returns the record class. In dynamic update packets, this field is known as "zclass" and refers to the zone's class.
print
$question->print;
Prints the question record on the standard output.
string
print $qr->string, "
";
Returns a string representation of the question record.
data
$qdata = $question->data($packet, $offset);
Returns the question record in binary format suitable for inclusion in a DNS packet.
Arguments are a "Net::DNS::Packet" object and the offset within that packet's data where the "Net::DNS::Question" record is to be stored.
This information is necessary for using compressed domain names.
COPYRIGHT
Copyright (c) 1997-2002 Michael Fuhr.
Portions Copyright (c) 2002-2004 Chris Reinhardt.
Portions Copyright (c) 2003,2006-2009 Dick Franks.
All rights reserved.
This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.
SEE ALSO
perl(1), Net::DNS, Net::DNS::Resolver, Net::DNS::Packet, Net::DNS::Update, Net::DNS::Header, Net::DNS::RR, RFC 1035 Section 4.1.2
perl v5.14.2 2009-12-30 Net::DNS::Question(3pm)