Below is the program i tried to execute......
main()
{
static int a = {0,1,2,3,4};
static int *p = {a, a+1, a+2, a+3, a+4};
printf (“\n %u %u %d”, p, *p, *(*p) );
}
This works, but i wanted to know why both a and *p are declared as "static". If we dont declare a as static... (2 Replies)
Hi all
i wonder about function pointers as i never used them in my C code .
could any tell me why and where exactly function pointers come into
picture .
thanq (1 Reply)
Hi I mash with pointers in C. I solve this problem about 5 hours and I don't know how I should continue.
void InsertFirst (tList *L, int val) {
tElemPtr new;
if((new = malloc(sizeof(tElemPtr))) == NULL) Error();
new->data = val;
new->ptr = L->frst;
L->frst = new;... (2 Replies)
Hi all. I am trying to use restricted pointers to allow the gcc compiler optimize the code, but I have not been able to make it work so far. I am testing with this code:
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <sys/time.h>
void vecmult(int n, int * restrict a, int... (0 Replies)
I am new to shared pointer conceot in C++ and hence require some clarification:
For example:
class A
{
public:
virtual ~A()
{
}
int x;
};
typedef boost::shared_ptr<A>... (1 Reply)
I have a special character called ô. When it is declared as a character variable its showing it can be printed. But when it is declared as a character pointer variable its showing it cannot be printed. I am just wondering why its happening like this..
c1 = '@';
c2 = 'ô';
char *fp;
fp="XXô";
if... (1 Reply)
Hi guys, I'm trying to understand pointers in C and made a simple example and I've problems with It.
Can someone help?
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
int f1(char **str_);
int main(int argc, char **argv)
{
char *str = NULL;
f1(&str);
... (3 Replies)
Hello, I read from a book exercise for a challenge. How to print out each letter of char array a by two different pointers pa and ppa in the example?
I have tried my code for letter "r" by testing without full understanding as only the first one worked.
#include<stdio.h>
int main()
{
char... (17 Replies)
Discussion started by: yifangt
17 Replies
LEARN ABOUT MOJAVE
tcl_attemptalloc
Tcl_Alloc(3) Tcl Library Procedures Tcl_Alloc(3)__________________________________________________________________________________________________________________________________________________NAME
Tcl_Alloc, Tcl_Free, Tcl_Realloc, Tcl_AttemptAlloc, Tcl_AttemptRealloc, ckalloc, ckfree, ckrealloc, attemptckalloc, attemptckrealloc -
allocate or free heap memory
SYNOPSIS
#include <tcl.h>
char *
Tcl_Alloc(size)
void
Tcl_Free(ptr)
char *
Tcl_Realloc(ptr, size)
char *
Tcl_AttemptAlloc(size)
char *
Tcl_AttemptRealloc(ptr, size)
char *
ckalloc(size)
void
ckfree(ptr)
char *
ckrealloc(ptr, size)
char *
attemptckalloc(size)
char *
attemptckrealloc(ptr, size)
ARGUMENTS
unsigned int size (in) Size in bytes of the memory block to allocate.
char *ptr (in) Pointer to memory block to free or realloc.
_________________________________________________________________DESCRIPTION
These procedures provide a platform and compiler independent interface for memory allocation. Programs that need to transfer ownership of
memory blocks between Tcl and other modules should use these routines rather than the native malloc() and free() routines provided by the C
run-time library.
Tcl_Alloc returns a pointer to a block of at least size bytes suitably aligned for any use.
Tcl_Free makes the space referred to by ptr available for further allocation.
Tcl_Realloc changes the size of the block pointed to by ptr to size bytes and returns a pointer to the new block. The contents will be
unchanged up to the lesser of the new and old sizes. The returned location may be different from ptr. If ptr is NULL, this is equivalent
to calling Tcl_Alloc with just the size argument.
Tcl_AttemptAlloc and Tcl_AttemptRealloc are identical in function to Tcl_Alloc and Tcl_Realloc, except that Tcl_AttemptAlloc and
Tcl_AttemptRealloc will not cause the Tcl interpreter to panic if the memory allocation fails. If the allocation fails, these functions
will return NULL. Note that on some platforms, but not all, attempting to allocate a zero-sized block of memory will also cause these
functions to return NULL.
The procedures ckalloc, ckfree, ckrealloc, attemptckalloc, and attemptckrealloc are implemented as macros. Normally, they are synonyms for
the corresponding procedures documented on this page. When Tcl and all modules calling Tcl are compiled with TCL_MEM_DEBUG defined, how-
ever, these macros are redefined to be special debugging versions of these procedures. To support Tcl's memory debugging within a module,
use the macros rather than direct calls to Tcl_Alloc, etc.
KEYWORDS
alloc, allocation, free, malloc, memory, realloc, TCL_MEM_DEBUG
Tcl 7.5 Tcl_Alloc(3)