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rsrcdbmgr_create()

Create a system resource

Synopsis:

#include <sys/rsrcdbmgr.h>
#include <sys/rsrcdbmsg.h>

int rsrcdbmgr_create( rsrc_alloc_t *item,
                      int count );

Arguments:

item

An array of rsrc_alloc_t structures that describe the resources that you want to create; see below.

count

The number of entries in the array.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The rsrcdbmgr_create() function creates one or more system resources. If the function completes successfully, count resources are returned in item.

rsrc_alloc_t structure

The structure of a basic resource request looks like this:

typedef struct _rsrc_alloc {
	_Uint64t	start;
	_Uint64t	end;
	_Uint32t	flags;
	const char	*name;
} rsrc_alloc_t;

The members include:

start, end

The resource range.

flags

The type of the resource, as well as flags that affect the request. You must set this member to be one of the following resource types (defined in <sys/rsrcdbmgr.h>):

• RSRCDBMGR_DMA_CHANNEL — DMA channel
• RSRCDBMGR_IO_PORT — I/O port address
• RSRCDBMGR_IRQ or RSRCMGR_IRQ — interrupt address
• RSRCDBMGR_MEMORY — Memory address
• RSRCDBMGR_PCI_MEMORY — PCI memory address

You can OR in the following bits (also defined in <sys/rsrcdbmgr.h>):

• RSRCDBMGR_FLAG_NAME — the name field is valid, and is a system name.
• RSRCDBMGR_FLAG_NOREMOVE — don't remove this resource when the process dies.
• RSRCDBMGR_FLAG_RSVP — create and reserve a resource with a higher priority than other resources. The resource is given out only when there are no other valid ranges available.

name

NULL, or a pointer to the name of the resource class. This field is used only if you set RSRCDBMGR_FLAG_NAME in the flags field. For more information, see rsrcdbmgr_attach().

You must set all the members.

Returns:

EOK, or -1 if an error occurred (errno is set).

Errors:

EAGAIN

The resource request can't be created.

EINVAL

Invalid argument.

ENOMEM

Insufficient memory to allocate internal data structures.

Examples:

/*
 * Create two resources:
 * 0-4K memory allocation and 5 DMA channels.
 */
#include <stdio.h>
#include <sys/rsrcdbmgr.h>
#include <sys/rsrcdbmsg.h>

int main(int argc, char **argv) {
    rsrc_alloc_t alloc[2];

    memset(alloc, 0, 2* sizeof(*alloc));
    alloc[0].start = 0;
    alloc[0].end = 4*1024; 
    alloc[0].flags = RSRCDBMGR_MEMORY;

    alloc[1].start = 1;
    alloc[1].end = 5;
    alloc[1].flags = RSRCDBMGR_DMA_CHANNEL;

    /* Allocate resources to the system. */
    if (rsrcdbmgr_create( alloc, 2 ) == -1) {
        perror("Problem creating resources \n");
        exit(1);
    }

    …
    /* Do something with the created resource */
    …

    /* Remove the allocated resources. */
    rsrcdbmgr_destroy ( alloc, 2 );

    return(0);
}

Classification:

QNX Neutrino

See also:

rsrcdbmgr_attach(), rsrcdbmgr_destroy()