I'd just like to add that a good way to use realloc is to assign to a temp variable rather then the variable you are copying from. That way if realloc fails you haven't lost the memory in your original variable. i.e.
Work problem:
Need to set up a job to periodically check that the number of entries in the mail queue.
I'm able to do the following: mailq | grep "Mail Queue"
Which returns: Mail Queue (7 requests)
Unfortunately I'm not sure how I select between `(` and `requests`?
... (2 Replies)
Hi guys, I hope you can help me with my problem.
I have a text file that contains lines like this:
78 ANGELO -809.05
79 ANGELO2 -5,000.06
I need to find all occurences of amounts that are negative and replace them with x's
78 ANGELO xxxxxxx
79... (4 Replies)
Hello All,
Plz help me with:
I have a csv file with data separated by ',' and optionally enclosed by "". I want to check each of these values to see if they exceed the specified string length, and if they do I want to cut just that value to the max length allowed and keep the csv format as it... (9 Replies)
hi,
im quite new to perl regexp. i have a problem where i want to extract a word from a given string. but the word is unknown, only fact is that it appears as the second word in the string.
Eg.
input string(s) :
char var1 = 'A';
int var2 = 10;
char *ptr;
and what i want to do is... (3 Replies)
Dear friends, Please help me to resolve the problem below,
I have a file with following content:
date of file creation : 12 feb 2007
====================
= name : suresh
= city :mumbai
#this is a blank line
= date : 1st Nov 2005
====================
few lines of some text
this... (7 Replies)
HI
In my script, i am reading the input from the user and want to find the length of the string.
The input may contain leading spaces. Right now, when leading spaces are there, they are not counted.
Kindly help me
My script is like below. I am using the ksh.
#!/usr/bin/ksh
echo... (2 Replies)
I have a string:
hgLogOutput=" +0000 files: forum/web/hook-test.txt /forum/web/hook-test-2.txt description: test"
and I want to extract the file names from it, they will always appear between the files: and the description:. I have worked out that I can do this:
"$hgLogOutput" | awk '{... (2 Replies)
I’m looking for an elegant way to convert a delimited file (comma delimited in this case) to padded columns (for printing in non-proportional font) but the length of each column is not known ahead of time. It needs to be calculated for each column from the longest entry in that column in a given... (3 Replies)
Hi
I have a file which contains wrong XML, There are some garbage characters at the end of line that I want to get rid of. Example:
<request type="product" ><attributes><pair><name>q</name><value><!]></value></pair><pair><name>start</name><value>1</value></pair></attributes></request>�J ... (7 Replies)
Discussion started by: dirtyd0ggy
7 Replies
LEARN ABOUT NETBSD
malloc
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