I have a function to which I will pass a struct ID and it will return me a string.
I will pass a pointer to store the name string and that pointer will be allocated memory by the function called.
The function ConvertIDToName() fails to store the allocated memory address in the void pointer.
I am unable to assign memory in the pointer and it gives me error from 3rd statement of function ConvertIDToName():
What am I doing wrong?
---------- Post updated at 02:33 AM ---------- Previous update was at 02:32 AM ----------
I missed the simple thing of typecasting the void pointer before using it.
This solves the issue:
First and foremost, this is not a homework for your information. I'm just new to using c-shell programming and I just wanted to make my life easier @ work.
Say, the file contains the following:
ID FILE NO. SL VP
1 1 22 33
1 2 ... (3 Replies)
Hello all
im trying to build function that will return void function pointer
what is mean is ( not working )
the main function
void * myClass::getFunction(int type){
if(type==1)
return &myClass::Test1;
if(type==2)
return &myClass::Test2;
}
void myClass::Test1(){... (1 Reply)
What is the difference between f(...) , f(void),f()
I know that f(void) doesn't take any parameters, but what about f() and f(...) Does the last call of function even exists? (2 Replies)
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)
N00B here. This function would be easier using a char pointer along with free. But I wish to learn how to use char static pointers (they do not require free, right ?).
How do I erase the content of a static pointer ? Terminating the string works but the static pointer's content is not being... (4 Replies)
i am trying to convert void pointer to pthread_t on hpux-itanium 64 bit which fails as below
"src/file.cpp", line 88: error #2171: invalid type conversion
pthread_t tid = reinterpret_cast<pthread_t>(m_threadId);
1 error detected in the compilation of "src/file.cpp"
... (0 Replies)
hi guys!
Is there such a thing as double void pointer dynamic allocation?
And if so is it something like this?
int n;
void** a;
a=malloc(n*sizeof(void*)); (12 Replies)
Discussion started by: vlm
12 Replies
LEARN ABOUT V7
malloc
MALLOC(3) Library Functions Manual MALLOC(3)NAME
malloc, free, realloc, calloc - main memory allocator
SYNOPSIS
char *malloc(size)
unsigned size;
free(ptr)
char *ptr;
char *realloc(ptr, size)
char *ptr;
unsigned size;
char *calloc(nelem, elsize)
unsigned nelem, elsize;
DESCRIPTION
Malloc and free provide a simple general-purpose memory allocation package. Malloc returns a pointer to a block of at least size bytes
beginning on a word boundary.
The argument to free is a pointer to a block previously allocated by malloc; this space is made available for further allocation, but its
contents are left undisturbed.
Needless to say, grave disorder will result if the space assigned by malloc is overrun or if some random number is handed to free.
Malloc allocates the first big enough contiguous reach of free space found in a circular search from the last block allocated or freed,
coalescing adjacent free blocks as it searches. It calls sbrk (see break(2)) to get more memory from the system when there is no suitable
space already free.
Realloc changes the size of the block pointed to by ptr to size bytes and returns a pointer to the (possibly moved) block. The contents
will be unchanged up to the lesser of the new and old sizes.
Realloc also works if ptr points to a block freed since the last call of malloc, realloc or calloc; thus sequences of free, malloc and
realloc can exploit the search strategy of malloc to do storage compaction.
Calloc allocates space for an array of nelem elements of size elsize. The space is initialized to zeros.
Each of the allocation routines returns a pointer to space suitably aligned (after possible pointer coercion) for storage of any type of
object.
DIAGNOSTICS
Malloc, realloc and calloc return a null pointer (0) if there is no available memory or if the arena has been detectably corrupted by stor-
ing outside the bounds of a block. Malloc may be recompiled to check the arena very stringently on every transaction; see the source code.
BUGS
When realloc returns 0, the block pointed to by ptr may be destroyed.
MALLOC(3)