Obtain segment-specific information about mapped memory segments in the process associated with the file descriptor. This call matches the corresponding mmap() calls.
#include <sys/procfs.h> #define DCMD_PROC_MAPINFO __DIOF(_DCMD_PROC, __PROC_SUBCMD_PROCFS + 2, procfs_mapinfo)
The arguments to devctl() are:
Argument | Value |
---|---|
filedes | A file descriptor for the process. |
dcmd | DCMD_PROC_MAPINFO |
dev_data_ptr | NULL, or an array of procfs_mapinfo structures |
n_bytes | 0, or the size of the array |
dev_info_ptr | A pointer to an integer where the number of map entries can be stored |
Call this the first time with an argument of NULL to get the number of map entries:
devctl( fd, DCMD_PROC_MAPINFO, NULL, 0, &n);
Next, allocate a buffer that's large enough to hold a procfs_mapinfo structure for each map entry, and pass it to another devctl() call:
my_buffer = (procfs_mapinfo *) malloc( sizeof(procfs_mapinfo) * n ); if ( my_buffer == NULL ) { /* Not enough memory. */ } devctl( fd, DCMD_PROC_MAPINFO, my_buffer, sizeof(procfs_mapinfo) * n, &dummy);
For more information, see the section on DCMD_PROC_MAPINFO and DCMD_PROC_PAGEDATA in the appendix about the /procfs filesystem in The QNX Neutrino Cookbook.