I was hoping someone could look at the code below and tell me if readjust_descr will clear all null pointers from the structure descr_list.
Depends what you mean by that. I believe you're trying to remove elements where state==0, but your attempt may crash frequently, being that it uses the contents of l after it's freed! And does so to no effect anyway, since r is equal to l -- you're just assigning the member to itself.
It would be helpful if you posted your data structures.
calloc doesn't give you 9 individual chunks of memory for one calloc of 9 elements, it gives you one big chunk large enough to hold 9 elements. You access further elements the same way you'd use any other array -- arrays just being locations in memory too.
I am facing a problem in replacing the file contents by iterating through the list.
My present code:
Code:
#!/bin/bash#
TFILE="/tmp/vinay/testb_1.txt"
while read linedo
aline="$line"
echo $aline
code=`echo $aline|cut -d ',' -f1`
country=`echo $aline|cut -d... (5 Replies)
hi all,
i am writing a ksh script, i am logging into an oracle db via sqlplus and running a select statement but i dont know how i can store the results from the sql so i can iterate over it and do more operations over it. I dont want to write a stored procedure with a cursor since i need to... (2 Replies)
Hey everyone.
Is it possible to use two arrays in a loop?
Basically what I am trying to do is iterate through the elements in an array, and, based on a condition, use the current position in the array to point to that index in the array. Here's the loop structure I'm looking for:
... (1 Reply)
Hello all,
I have a confusion with calloc function :
wz. the difference between the following 2 statemnts:
char *ptr;
char = (char*)calloc(num, sizeof(char));
char = (char*)calloc(num, sizeof(char*));
Am really confused!!!!!
---------- Post updated at 09:32 AM... (1 Reply)
Hello, I am working on a coding project for a class and to test the program I have created, I have come up with 100 different test cases. The program takes four text files as input, so each of the test cases is contained in a folder with four files.
I have a folder called 'tests', within which... (1 Reply)
Hi,
I've recently started using Awk commands as i need it to pull information out of a file and give me the mean value of a series of numbers. Here is the code i run on my Infile and it works just fine.
awk '{if ($1 == "Mam189") print $0}' Infile | awk '{if ($1 != $2) print $0}' | awk... (5 Replies)
Hi , experts.
I work on Linux station (RedHat 5.7), regular user, but have root password.
%> uname -a
Linux ran1log06 2.6.18-238.1.1.el5 #1 SMP Tue Jan 4 13:32:19 EST 2011 x86_64 x86_64 x86_64 GNU/Linux
%> cat /etc/issue
Red Hat Enterprise Linux Client release 5.7 (Tikanga)
Kernel \r on... (5 Replies)
I need to run the same awk function over an entire directly of files.
This is the awk:
awk '{$(NF+1)=1}1'
Is there a way that I can run this command once over all of the files, along the lines of:
awk '{$(NF+1)=1}1' *
so that I do not have to run this several times?
My main concern is... (2 Replies)
Hi,
I am trying to do something similar to the for loop example from KSH For Loop Array: Iterate Through Array Values
$: cat y.ksh
#!/bin/ksh
# set array called nameservers
set -A nameservers 192.168.1.1 192.168.1.5 202.54.1.5
# print all name servers
for i in ${nameservers}
do
... (3 Replies)
Discussion started by: newbie_01
3 Replies
LEARN ABOUT NETBSD
realloc
MALLOC(3) BSD Library Functions Manual MALLOC(3)NAME
malloc, calloc, realloc, free -- general purpose memory allocation functions
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
void *
malloc(size_t size);
void *
calloc(size_t number, size_t size);
void *
realloc(void *ptr, size_t size);
void
free(void *ptr);
DESCRIPTION
The malloc() function allocates size bytes of uninitialized memory. The allocated space is suitably aligned (after possible pointer coer-
cion) for storage of any type of object.
The calloc() function allocates space for number objects, each size bytes in length. The result is identical to calling malloc() with an
argument of ``number * size'', with the exception that the allocated memory is explicitly initialized to zero bytes.
The realloc() function changes the size of the previously allocated memory referenced by ptr to size bytes. The contents of the memory are
unchanged up to the lesser of the new and old sizes. If the new size is larger, the value of the newly allocated portion of the memory is
undefined. Upon success, the memory referenced by ptr is freed and a pointer to the newly allocated memory is returned. Note that realloc()
may move the memory allocation, resulting in a different return value than ptr. If ptr is NULL, the realloc() function behaves identically
to malloc() for the specified size.
The free() function causes the allocated memory referenced by ptr to be made available for future allocations. If ptr is NULL, no action
occurs.
RETURN VALUES
The malloc() and calloc() functions return a pointer to the allocated memory if successful; otherwise a NULL pointer is returned and errno is
set to ENOMEM.
The realloc() function returns a pointer, possibly identical to ptr, to the allocated memory if successful; otherwise a NULL pointer is
returned, and errno is set to ENOMEM if the error was the result of an allocation failure. The realloc() function always leaves the original
buffer intact when an error occurs.
The free() function returns no value.
EXAMPLES
When using malloc(), be careful to avoid the following idiom:
if ((p = malloc(number * size)) == NULL)
err(EXIT_FAILURE, "malloc");
The multiplication may lead to an integer overflow. To avoid this, calloc() is recommended.
If malloc() must be used, be sure to test for overflow:
if (size && number > SIZE_MAX / size) {
errno = EOVERFLOW;
err(EXIT_FAILURE, "allocation");
}
When using realloc(), one must be careful to avoid the following idiom:
nsize += 50;
if ((p = realloc(p, nsize)) == NULL)
return NULL;
Do not adjust the variable describing how much memory has been allocated until it is known that the allocation has been successful. This can
cause aberrant program behavior if the incorrect size value is used. In most cases, the above example will also leak memory. As stated ear-
lier, a return value of NULL indicates that the old object still remains allocated. Better code looks like this:
newsize = size + 50;
if ((p2 = realloc(p, newsize)) == NULL) {
if (p != NULL)
free(p);
p = NULL;
return NULL;
}
p = p2;
size = newsize;
SEE ALSO madvise(2), mmap(2), sbrk(2), alloca(3), atexit(3), getpagesize(3), memory(3), posix_memalign(3)
For the implementation details, see jemalloc(3).
STANDARDS
The malloc(), calloc(), realloc() and free() functions conform to ISO/IEC 9899:1990 (``ISO C90'').
BSD May 3, 2010 BSD