Using standard C library sysconf is very simple.

See all about sysconf.

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NAME
     sysconf -- get configurable system variables
 
LIBRARY
     Standard C Library (libc, -lc)
 
SYNOPSIS
     #include
 
     long
     sysconf(int name);
 
DESCRIPTION
     This interface is defined by IEEE Std 1003.1-1988 (``POSIX.1'').  A far
     more complete interface is available using sysctl(3).
 
     The sysconf() function provides a method for applications to determine
     the current value of a configurable system limit or option variable.  The
     name argument specifies the system variable to be queried.  Symbolic con-
     stants for each name value are found in the include file .
     Shell programmers who need access to these parameters should use the
     getconf(1) utility.
 
     The available values are as follows:
 
     _SC_ARG_MAX
     The maximum bytes of argument to execve(2).
 
     _SC_CHILD_MAX
     The maximum number of simultaneous processes per user id.
 
     _SC_CLK_TCK
     The frequency of the statistics clock in ticks per second.
 
     _SC_IOV_MAX
     The maximum number of elements in the I/O vector used by
     readv(2), writev(2), recvmsg(2), and sendmsg(2).
 
     _SC_NGROUPS_MAX
     The maximum number of supplemental groups.
 
     _SC_NPROCESSORS_CONF
     The number of processors configured.
 
     _SC_NPROCESSORS_ONLN
     The number of processors currently online.
 
     _SC_OPEN_MAX
     The maximum number of open files per user id.
 
     _SC_PAGESIZE
     The size of a system page in bytes.
 
     _SC_STREAM_MAX
     The minimum maximum number of streams that a process may have
     open at any one time.
 
     _SC_TZNAME_MAX
     The minimum maximum number of types supported for the name of a
     timezone.
 
     _SC_JOB_CONTROL
     Return 1 if job control is available on this system, otherwise
     -1.
 
     _SC_SAVED_IDS
     Returns 1 if saved set-group and saved set-user ID is available,
     otherwise -1.
 
     _SC_VERSION
     The version of IEEE Std 1003.1 (``POSIX.1'') with which the sys-
     tem attempts to comply.
 
     _SC_BC_BASE_MAX
     The maximum ibase/obase values in the bc(1) utility.
 
     _SC_BC_DIM_MAX
     The maximum array size in the bc(1) utility.
 
     _SC_BC_SCALE_MAX
     The maximum scale value in the bc(1) utility.
 
     _SC_BC_STRING_MAX
     The maximum string length in the bc(1) utility.
 
     _SC_COLL_WEIGHTS_MAX
     The maximum number of weights that can be assigned to any entry
     of the LC_COLLATE order keyword in the locale definition file.
 
     _SC_EXPR_NEST_MAX
     The maximum number of expressions that can be nested within
     parenthesis by the expr(1) utility.
 
     _SC_LINE_MAX
     The maximum length in bytes of a text-processing utility's input
     line.
 
     _SC_RE_DUP_MAX
     The maximum number of repeated occurrences of a regular expres-
     sion permitted when using interval notation.
 
     _SC_2_VERSION
     The version of IEEE Std 1003.2 (``POSIX.2'') with which the sys-
     tem attempts to comply.
 
     _SC_2_C_BIND
     Return 1 if the system's C-language development facilities sup-
     port the C-Language Bindings Option, otherwise -1.
 
     _SC_2_C_DEV
     Return 1 if the system supports the C-Language Development Utili-
     ties Option, otherwise -1.
 
     _SC_2_CHAR_TERM
     Return 1 if the system supports at least one terminal type capa-
     ble of all operations described in IEEE Std 1003.2 (``POSIX.2''),
     otherwise -1.
 
     _SC_2_FORT_DEV
     Return 1 if the system supports the FORTRAN Development Utilities
     Option, otherwise -1.
 
     _SC_2_FORT_RUN
     Return 1 if the system supports the FORTRAN Runtime Utilities
     Option, otherwise -1.
 
     _SC_2_LOCALEDEF
     Return 1 if the system supports the creation of locales, other-
     wise -1.
 
     _SC_2_SW_DEV
     Return 1 if the system supports the Software Development Utili-
     ties Option, otherwise -1.
 
     _SC_2_UPE
     Return 1 if the system supports the User Portability Utilities
     Option, otherwise -1.
 
     These values also exist, but may not be standard:
 
     _SC_PHYS_PAGES
     The number of pages of physical memory.  Note that it is possible
     that the product of this value and the value of _SC_PAGESIZE will
     overflow a long in some configurations on a 32bit machine.

The source code is this:

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#include
#include
 
main() {
long tmp,tmp2;
tmp=sysconf(_SC_NPROCESSORS_CONF);
tmp2=sysconf(_SC_CLK_TCK);
if(tmp==-1 && tmp2==-1)
        printf("Check the argument passed to sysconf");
else
 
printf("Processors : %d \n",tmp);
 
printf("Clock ticks/second: %d \n",tmp2);
}

I use stdio.h and unistd.h libs. Also, I have two vars tmp and tmp2.

This vars will take the result of _SC_NPROCESSORS_CONF and _SC_CLK_TCK using sysconf.

Use the gcc to make binary.

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$ gcc  sysconf-test.c -o sysconf-test

… run it and we see the output.

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$ ./sysconf-test
Processors : 1
Clock ticks/second: 100

We can also use all of these available parameters.

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