|This version of this document is no longer maintained. For the latest documentation, see http://www.qnx.com/developers/docs.|
Get information about a typed memory object
#include <sys/mman.h> int posix_typed_mem_get_info( int fildes, struct posix_typed_mem_info *info);
- The file descriptor for the typed memory object that you want to query, returned by a call to posix_typed_mem_open().
- A pointer to a posix_typed_mem_info structure where the function can store the information.
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The posix_typed_mem_get_info() function queries the typed memory object to obtain the amount of memory currently available. This is particularly important for typed memory objects that may in some cases be scarce resources.
|This function was added in the QNX Neutrino Core OS 6.3.2.|
The posix_typed_mem_get_info() function stores, in the posix_tmi_length field of the posix_typed_mem_info structure pointed to by info, the maximum length that may be successfully allocated by the typed memory object designated by fildes.
|If the typed memory pool is a shared resource, some form of mutual-exclusion or synchronization may be required while querying and allocating it, to prevent race conditions.|
The maximum length is dynamic; it's valid only while the current mapping of the corresponding typed memory pool remains unchanged. It takes into account the POSIX_TYPED_MEM_ALLOCATE or POSIX_TYPED_MEM_ALLOCATE_CONTIG flag specified when the typed memory object was opened.
As a Neutrino extension, if fildes represents a typed memory object opened with neither POSIX_TYPED_MEM_ALLOCATE nor POSIX_TYPED_MEM_ALLOCATE_CONTIG, the function sets info->posix_tmi_length to 0.
- The fildes argument isn't a valid open file descriptor.
- The fildes isn't connected to a memory object supported by this function.
“Typed memory” in the Interprocess Communication (IPC) chapter of the System Architecture guide