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Full Discussion: Malloc - unlimited input from user
Homework and Emergencies Homework & Coursework Questions Malloc - unlimited input from user Post 302777077 by Corona688 on Thursday 7th of March 2013 10:33:23 AM
Old 03-07-2013
You're using too many *'s. Wherever you see * in front, imagine an [] at the end: ** would be an array of arrays.

sizeof(char **) doesn't make sense either. You want 5000 characters. How large is one character? sizeof(char). How large is 5000 of them? sizeof(char) * 5000.

Code:
char *buffer=(char *)malloc(sizeof(char)*5000);

Next, you don't need strncmp, strcmp() will do. fgets() and the like NULL-terminate their strings properly.

Last, how do you handle unlimited input? you can use realloc() to extend the size of an existing block of memory.

Code:
buffer=realloc(buffer, 10000*sizeof(char));

You can even call realloc() on a NULL pointer(pointer to nothing) -- it will know to just give you fresh data. So you can just run the exact same code every loop, the first time isn't anything special.

So:

Code:
int main(void)
{
        int pos=0; // pos:  how many bytes have been read already
        int size=0; // size:  how large the buffer is
        char *buffer=NULL; // The data buffer

        buffer=realloc(buffer, pos+5000); // Add 5000 more bytes.
        if(buffer == NULL)
        {
                printf("out of memory\n");
                return(1);
        }
        size=pos+5000; // We need 5000 bytes past the end of the last data
        fgets(buffer+pos, 5000, stdin); // Read it 'pos' bytes past the start of the buffer, to add to the end
        pos=strlen(buffer); // How long is the data in the buffer now?
}

 

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LEARN ABOUT DEBIAN

ldns_wire2rdf

ldns(3) 						     Library Functions Manual							   ldns(3)

NAME

       ldns_wire2rr, ldns_wire2pkt, ldns_wire2rdf, ldns_wire2dname-

SYNOPSIS

       #include <stdint.h>
       #include <stdbool.h>

       #include <ldns/ldns.h>

       ldns_status ldns_wire2rr(ldns_rr **rr, const uint8_t *wire, size_t max, size_t *pos, ldns_pkt_section section);

	ldns_wire2pkt();

       ldns_status ldns_wire2rdf(ldns_rr *rr, const uint8_t *wire, size_t max, size_t *pos);

       ldns_status ldns_wire2dname(ldns_rdf **dname, const uint8_t *wire, size_t max, size_t *pos);

DESCRIPTION

       ldns_wire2rr()  converts  the  data  on the uint8_t bytearray (in wire format) to a DNS resource record.  This function will initialize and
	      allocate memory space for the rr structure.  The length of the wiredata of this rr is added to the *pos value.

	      rr: pointer to the structure to hold the rdata value
	      wire: pointer to the buffer with the data
	      max: the length of the data buffer (in bytes)
	      pos: the position of the rr in the buffer (ie. the number of bytes
			 from the start of the buffer)
	      section: the section in the packet the rr is meant for
	      Returns LDNS_STATUS_OK if everything succeeds, error otherwise

       ldns_wire2pkt()

       ldns_wire2rdf() converts the data on the uint8_t bytearray (in wire format) to DNS rdata fields, and adds them to the list of rdfs  of  the
	      given  rr.   This  function will initialize and allocate memory space for the dname structures.  The length of the wiredata of these
	      rdfs is added to the *pos value.

	      All rdfs belonging to the RR are read; the rr should have no rdfs yet. An error is returned if the format cannot be parsed.

	      rr: pointer to the ldns_rr structure to hold the rdata value
	      wire: pointer to the buffer with the data
	      max: the length of the data buffer (in bytes)
	      pos: the position of the rdf in the buffer (ie. the number of bytes
			 from the start of the buffer)
	      Returns LDNS_STATUS_OK if everything succeeds, error otherwise

       ldns_wire2dname() converts the data on the uint8_t bytearray (in wire format) to a DNS dname rdata field. This function will initialize and
	      allocate memory space for the dname structure. The length of the wiredata of this rdf is added to the *pos value.

	      dname: pointer to the structure to hold the rdata value
	      wire: pointer to the buffer with the data
	      max: the length of the data buffer (in bytes)
	      pos: the position of the rdf in the buffer (ie. the number of bytes
			 from the start of the buffer)
	      Returns LDNS_STATUS_OK if everything succeeds, error otherwise

AUTHOR

       The ldns team at NLnet Labs. Which consists out of Jelte Jansen and Miek Gieben.

REPORTING BUGS

       Please report bugs to ldns-team@nlnetlabs.nl or in our bugzilla at http://www.nlnetlabs.nl/bugs/index.html

COPYRIGHT

       Copyright (c) 2004 - 2006 NLnet Labs.

       Licensed under the BSD License. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       ldns_rr2wire, ldns_pkt2wire, ldns_rdf2wire, ldns_dname2wire.  And perldoc Net::DNS, RFC1034, RFC1035, RFC4033, RFC4034  and RFC4035.

REMARKS

       This manpage was automaticly generated from the ldns source code by use of Doxygen and some perl.

								    30 May 2006 							   ldns(3)
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