media_getid

- return the id of a piece of media

Synopsis

cc [flag …] file …-lvolgmt [library …] 

#include <volmgt.h>



ulonglong_t media_getid(char *vol_path);

Description

media_getid() returns the id of a piece of media. Volume Management must be running. See volmgt_running(3VOLMGT).

Parameters

vol_path

Path to the block or character special device.

Return Values

media_getid() returns the id of the volume. This value is unique for each volume. If media_getid() returns 0, the path provided is not valid, for example, it is a block or char device.

Examples

Example 1 Using media_getid()

The following example first checks if Volume Management is running, then checks the volume management name space for path, and then returns the id for the piece of media.

char *path;

    ...

if (volmgt_running()) {
     if (volmgt_ownspath(path)) {
          (void) printf("id of %s is %lld\n",
               path, media_getid(path));
     }
    }

If a program using media_getid() does not check whether or not Volume Management is running, then any NULL return value will be ambiguous, as it could mean that either Volume Management does not have path in its name space, or Volume Management is not running.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

volmgt_ownspath(3VOLMGT),volmgt_running(3VOLMGT),attributes(5)