When you send a pointer you are NOT sending data. You are sending an address.
You are passing a reference, not the string of characters or binary data array you are pointing to. The reference on the other node is pointing to nothing. That is why you segfault. Unless your method is smart enough to create storage on the remote side and copy the array over there.
This User Gave Thanks to jim mcnamara For This Post:
I have a struct as follows...
struct A
{
int a;
ucontext_t X; //ucontext_t is another structure
}
How do I define a pointer to the above structure variable X of the type ucontext_t from within another function?
eg. void foo()
{
struct A a;
/////WHAT COMES IN... (1 Reply)
I am using a structure defined as follows
struct gene_square
{
double *x;
double *y;
};I have class, with a member function which is a pointer of this type:
gene_square* m_Genes;I am allocating memory in the constructors like this:
m_Genes = new gene_square;
for (ii=0;... (1 Reply)
If one wants to get a start address of a array or a string or a block of memory via a function, there are at least two methods to achieve it:
(1) one is to pass a pointer-to-pointer parameter, like:
int my_malloc(int size, char **pmem)
{
*pmem=(char *)malloc(size);
if(*pmem==NULL)... (11 Replies)
Suppose to have:
struct Tstudent
{
string name, surname;
int matriculation_num;
};
struct Tnode
{
Tstudent* student;
Tnodo* next;
} L;I want to deference that "student" pointer. For example, I tried with:
*(L->student).matriculation_numbut it not worked, as terminal... (4 Replies)
Hi,
Can any one tell me why my following program is crashing?
#include <iostream>
using namespace std;
class CA {
public:
const static int i;
};
const int CA::i = 10;
int main() {
int* pi = const_cast<int*>(&CA::i);
*pi = 9;
cout << CA::i << endl;
} (6 Replies)
I have what should be a relatively simple program (fadec.c) that maps a struct from an included header file (fadec.h) to a shared memory region, but I’m struggling accessing members in the struct from the pointer returned by shmat. Ultimately, I want to access members in the shared memory structure... (2 Replies)
Hi,
I have received an application that stores some properties in a file. The existing struct looks like this:
struct TData
{
UINT uSizeIncludingStrings;
// copy of Telnet data struct
UINT uSize;
// basic properties:
TCHAR szHost; //defined in Sshconfig
UINT iPortNr;
TCHAR... (2 Replies)
Hi guys ,
i got segment fault , and when i trace , found it happens since the value of pointer which is returned by Struct S_client (*ptr) is zero
if (ptr !=0)i know , adding above line of code is not the solution and not correct for the case since above line only check for the pointer... (1 Reply)
Hi all!
I am trying to register a device in an existing device class, but I am
having trouble getting the pointer to an existing class.
I can create a class in a module, get the pointer to it and then use
it to register the device with:
*cl = class_create(THIS_MODULE, className);... (0 Replies)
Discussion started by: hdaniel@ualg.pt
0 Replies
LEARN ABOUT CENTOS
tcl_setbytearraylength
Tcl_ByteArrayObj(3) Tcl Library Procedures Tcl_ByteArrayObj(3)__________________________________________________________________________________________________________________________________________________NAME
Tcl_NewByteArrayObj, Tcl_SetByteArrayObj, Tcl_GetByteArrayFromObj, Tcl_SetByteArrayLength - manipulate Tcl objects as a arrays of bytes
SYNOPSIS
#include <tcl.h>
Tcl_Obj *
Tcl_NewByteArrayObj(bytes, length)
void
Tcl_SetByteArrayObj(objPtr, bytes, length)
unsigned char *
Tcl_GetByteArrayFromObj(objPtr, lengthPtr)
unsigned char *
Tcl_SetByteArrayLength(objPtr, length)
ARGUMENTS
const unsigned char *bytes (in) The array of bytes used to initialize or set a byte-array object.
int length (in) The length of the array of bytes. It must be >= 0.
Tcl_Obj *objPtr (in/out) For Tcl_SetByteArrayObj, this points to the object to be converted to byte-array type. For
Tcl_GetByteArrayFromObj and Tcl_SetByteArrayLength, this points to the object from which to
get the byte-array value; if objPtr does not already point to a byte-array object, it will be
converted to one.
int *lengthPtr (out) If non-NULL, filled with the length of the array of bytes in the object.
_________________________________________________________________DESCRIPTION
These procedures are used to create, modify, and read Tcl byte-array objects from C code. Byte-array objects are typically used to hold
the results of binary IO operations or data structures created with the binary command. In Tcl, an array of bytes is not equivalent to a
string. Conceptually, a string is an array of Unicode characters, while a byte-array is an array of 8-bit quantities with no implicit
meaning. Accessor functions are provided to get the string representation of a byte-array or to convert an arbitrary object to a byte-
array. Obtaining the string representation of a byte-array object (by calling Tcl_GetStringFromObj) produces a properly formed UTF-8
sequence with a one-to-one mapping between the bytes in the internal representation and the UTF-8 characters in the string representation.
Tcl_NewByteArrayObj and Tcl_SetByteArrayObj will create a new object of byte-array type or modify an existing object to have a byte-array
type. Both of these procedures set the object's type to be byte-array and set the object's internal representation to a copy of the array
of bytes given by bytes. Tcl_NewByteArrayObj returns a pointer to a newly allocated object with a reference count of zero. Tcl_SetByteAr-
rayObj invalidates any old string representation and, if the object is not already a byte-array object, frees any old internal representa-
tion.
Tcl_GetByteArrayFromObj converts a Tcl object to byte-array type and returns a pointer to the object's new internal representation as an
array of bytes. The length of this array is stored in lengthPtr if lengthPtr is non-NULL. The storage for the array of bytes is owned by
the object and should not be freed. The contents of the array may be modified by the caller only if the object is not shared and the call-
er invalidates the string representation.
Tcl_SetByteArrayLength converts the Tcl object to byte-array type and changes the length of the object's internal representation as an
array of bytes. If length is greater than the space currently allocated for the array, the array is reallocated to the new length; the
newly allocated bytes at the end of the array have arbitrary values. If length is less than the space currently allocated for the array,
the length of array is reduced to the new length. The return value is a pointer to the object's new array of bytes.
SEE ALSO
Tcl_GetStringFromObj, Tcl_NewObj, Tcl_IncrRefCount, Tcl_DecrRefCount
KEYWORDS
object, byte array, utf, unicode, internationalization
Tcl 8.1 Tcl_ByteArrayObj(3)