Number of CPU Cores

Use the sysconf() function with the _SC_NPROCESSORS_CONF and _SC_NPROCESSORS_ONLN parameters specified:

_SC_NPROCESSORS_CONF: returns the number of CPU cores in the system. All CPU cores are counted even if some cannot be used by users.

_SC_NPROCESSORS_ONLN: returns the number of available CPU cores in the system.

Example:

#include "unistd.h"
printf("system cpu num is %d\n", sysconf( _SC_NPROCESSORS_CONF));
printf("system enable cpu num is %d\n", sysconf(_SC_NPROCESSORS_ONLN));

Use the get_nprocs_conf() and get_nprocs() functions to obtain the number of CPUs.

• get_nprocs_conf(): returns the number of all CPU cores in the current system.
• get_nprocs(): returns the number of CPU cores that can be used by the current user.

#include "sys/sysinfo.h"
printf("system cpu num is %d\n", get_nprocs_conf());
printf("system enable num is %d\n", get_nprocs());