Format
#include <stdlib.h>
void *malloc(size_t size);
Language Level: ANSI
Threadsafe: Yes.
Description
The malloc() function reserves a block of storage of size bytes. Unlike the calloc() function, malloc() does not initialize all elements to 0. The maximum size for a non-teraspace malloc() is 16711568 bytes.
For more information, see the ILE Concepts manual.
Return Value
The malloc() function returns a pointer to the reserved space. The storage space to which the return value points is suitably aligned for storage of any type of object. The return value is NULL if not enough storage is available, or if size was specified as zero.
Example that uses malloc()
This example prompts for the number of array entries you want and then reserves enough space in storage for the entries. If malloc() was successful, the example assigns values to the entries and prints out each entry; otherwise, it prints out an error.
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
long * array; /* start of the array */
long * index; /* index variable */
int i; /* index variable */
int num; /* number of entries of the array */
printf( "Enter the size of the array\n" );
scanf( "%i", &num );
/* allocate num entries */
if ( (index = array = (long *) malloc( num * sizeof( long ))) != NULL )
{
for ( i = 0; i < num; ++i ) /* put values in array */
*index++ = i; /* using pointer notation */
for ( i = 0; i < num; ++i ) /* print the array out */
printf( "array[ %i ] = %i\n", i, array[i] );
}
else { /* malloc error */
perror( "Out of storage" );
abort();
}
}
/******************** Output should be similar to: **************
Enter the size of the array
array[ 0 ] = 0
array[ 1 ] = 1
array[ 2 ] = 2
array[ 3 ] = 3
array[ 4 ] = 4
*/
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