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.
Notes:
All heap storage is associated with the activation
group of the calling routine. As such, storage should be allocated
and deallocated within the same activation group. You cannot allocate
heap storage within one activation group and deallocate that storage
from a different activation group. For more information about activation
groups, see the ILE Concepts manual.
To use teraspace storage instead of single-level
store storage without changing the C source code, specify the TERASPACE(*YES
*TSIFC) parameter on the compiler command. This maps the malloc() library
function to _C_TS_malloc(),
its teraspace storage counterpart. The maximum amount of teraspace
storage that can be allocated by each call to _C_TS_malloc() is
2GB - 224, or 2147483424 bytes. If more than 2147483408 bytes are
needed on a single request, call _C_TS_malloc64(unsigned long long int);.
For more
information, see the ILE Concepts manual.
For current statistics on the teraspace storage being used by
MI programs in an activation group, call the _C_TS_malloc_info function.
This function returns information including total bytes, allocated
bytes and blocks, unallocated bytes and blocks, requested bytes, pad
bytes, and overhead bytes. To get more detailed information about
the memory structures used by the _C_TS_malloc() and _C_TS_malloc64() functions,
call the _C_TS_malloc_debug() function. You can use the
information this function returns to identify memory corruption problems.
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 usesmalloc()
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
*/
To use teraspace storage instead of single-level
store storage without changing the C source code, specify the TERASPACE(*YES
*TSIFC) parameter on the compiler command. This maps the malloc() library
function to _C_TS_malloc(),
its teraspace storage counterpart. The maximum amount of teraspace
storage that can be allocated by each call to _C_TS_malloc() is
2GB - 224, or 2147483424 bytes. If more than 2147483408 bytes are
needed on a single request, call _C_TS_malloc64(unsigned long long int);.
