|
Can someone explain to me why my call to malloc with a string size of 6 returns a sizeof of 4 bytes? In fact, any integer argument I give malloc I get a sizeof of 4. Next, I am trying to copy two strings. Why is my ouput of the copied string (NULL)? Following...
Started by John on
, 8 posts
by 8 people.
Answer Snippets (Read the full thread at stackoverflow):
Char * str = "string"; /* char * copy = malloc(sizeof(str) + 1); Oops */ char * copy = malloc(strlen(str) + 1); charYou're getting....
To access the beginning of the string:
Edit to repair malloc/sizeof issue - thanks CL.
|
|
Someone here recently pointed out to me in a piece of code of mine I am using
char* name = malloc(256*sizeof(char)); // more code free(name);
I was under the impression that this way of setting up an array was identical to using
char name[256];
and that...
Started by faceless1_14 on
, 7 posts
by 7 people.
Answer Snippets (Read the full thread at stackoverflow):
Int *p = (int *) malloc....
; }
Break down your statement
char* name = malloc(256*sizeof(char)); // one statement char *name; // Step 1 declare pointer to character name = malloc(256*sizeof(char)); // assign address to pointer.
|
|
I have the following instance method (adapted from Listing 3-6 of the Event Handling section in the iPhone Application Programming Guide):
- (CGPoint)originOfTouch:(UITouch *)touch { CGPoint *touchOriginPoint = (CGPoint *)CFDictionaryGetValue(touchOriginPoints...
Started by Shaun Inman on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
Approach, you have to find a place to free those malloc -ed memory when the values are not needed.
|
Ask your Facebook Friends
|
Could you explain following code?
str = (char *) malloc (sizeof(char) * (num+1));
What's is malloc? Why num + 1?
Started by ffffff on
, 12 posts
by 12 people.
Answer Snippets (Read the full thread at stackoverflow):
For example:
int * p = (int *) malloc (25 * sizeof(int)) ;
Then p points to a memory where youmalloc is for memory....
The first problem is parsing the code
Welcome into the Twilight Zone str = (char *) malloc (sizeof as an array.
|
|
Possible Duplicate:
newbie questions about malloc and sizeof
I am trying to read strings into a program. When I noticed that the strings were sometimes being corrupted, I tried the following code:
void *mallocated = malloc(100); printf("sizeof(mallocated...
Started by Michael Dickens on
, 6 posts
by 6 people.
Answer Snippets (Read the full thread at stackoverflow):
What you probably want is
char (*s)[100] = malloc( sizeof( char[100] ) ); printfBecause the size of the "....
Still!
To know, possibly on the heap.
Or 8 on 64-bit architectures) char *p = malloc(100); // sizeof p == 4 (or 8).
|
|
Recently saw someone commending another user on their use of sizeof var instead of sizeof(type). I always thought that was just a style choice. Is there any significant difference? As an example, the lines with f and ff were considered better than the...
Started by jmucchiello on
, 7 posts
by 7 people.
Answer Snippets (Read the full thread at stackoverflow):
These:
foo **ff = malloc(count * sizeof *ff); foo **gg = malloc(sizeof(foo*) * count);
..but whatIf the type of the variable is changed, the sizeof will not require changing if the variable is the argument, rather than....
|
|
We recently received a report that our application will occasionally fail to run. I tracked down the problem code to this:
struct ARRAY2D { long[] col; } int numRows = 8 ; int numCols = 300; array = (ARRAY2D*) malloc(numRows * numCols * sizeof(long))
...
Started by Brian on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
ARRAY2D() { memset(col, 0, sizeof(col)); } }; // no need to malloc std::unordered_map<(numCols * sizeof(long*)); for (int i = 0; i < numCols; i++) array[i] = (long*) malloc(numRows * sizeof *rows....
Not necessary.
|
|
If I use malloc in my code:
int *x = malloc(sizeof(int));
I get this warning from gcc :
new.c:7: warning: implicit declaration of function ‘malloc’ new.c:7: warning: incompatible implicit declaration of built-in function ‘malloc’
I'm new to C. Am I doing...
Started by Lucas McCoy on
, 6 posts
by 6 people.
Answer Snippets (Read the full thread at stackoverflow):
If you don't do that, the compiler thinks you want to define your own function named malloc ....
To add typecast in addition to include
#include <stdlib.h> int *x = (int*)malloc(sizeof(int includes malloc 's declaration.
|
|
In this question , someone suggested in a comment that I should not cast the results of malloc. I.e.
int *sieve = malloc(sizeof(int)*length);
rather than
int *sieve = (int *)malloc(sizeof(int)*length);
Why would this be the case?
Started by Patrick McDonald on
, 9 posts
by 9 people.
Answer Snippets (Read the full thread at stackoverflow):
However, count) ((type *)calloc(count,....
The pointer to void returned by malloc is automagically cast to the correct type.
The community is to use the following:
int *sieve = malloc(sizeof *sieve * length);
which of malloc .
|
|
What is the difference between doing:
ptr = (char **) malloc (MAXELEMS * sizeof(char *)); // OR ptr = (char **) calloc (MAXELEMS, sizeof(char*));
???
EDT: When is it a good idea to use calloc over malloc or vice versa?
Answer Snippets (Read the full thread at stackoverflow):
EDIT:
Zeroing out the memory may take a little time, so you probably want to use malloc() if that performance memory allocation, like Linux, the pointer....
Calloc() zero-initializes the buffer, while malloc() leaves the memory uninitialized.
|
