C Syntax (Toggle Plain Text)

cat /proc/meminfo

cat /proc/meminfo

shows the current state of memory. The format varies somewhat with Linux distributions. My version of Linux has what you want in the 4 th column on the second line. So, you will need to get the awk statement working for you. Then put it in the C code.
You could also just read /proc/meminfo (read only) as a regular file and find the value using C only.
snippet:

C Syntax (Toggle Plain Text)

#include <stdio.h>
void foo(void)
{
   char *cmd="awk '{ if(NR==2){print $4}}' /proc/meminfo";
   FILE *cmdfile=popen(cmd,"r");
   char result[256]={0x0};
   while(fgets(result,sizeof(result),cmdfile)!=NULL) 
   {
       printf("%s\n",result);
   }
   pclose(cmdfile);
}

#include <stdio.h> void foo(void) { char *cmd="awk '{ if(NR==2){print $4}}' /proc/meminfo"; FILE *cmdfile=popen(cmd,"r"); char result[256]={0x0}; while(fgets(result,sizeof(result),cmdfile)!=NULL) { printf("%s\n",result); } pclose(cmdfile); }