Thread: Memory & Swap

Free works by simply parsing a dump of /proc/meminfo. You could write a function that reads data in from /proc/meminfo and returns specifics, such as available memory.

If you're not interested in parsing a dump from /proc/meminfo, check out sysinfo():

Code:

int sysinfo(struct sysinfo *info);

struct sysinfo {
  long uptime;             /* Seconds since boot */
  unsigned long loads[3];  /* 1, 5, and 15 minute load averages */
  unsigned long totalram;  /* Total usable main memory size */
  unsigned long freeram;   /* Available memory size */
  unsigned long sharedram; /* Amount of shared memory */
  unsigned long bufferram; /* Memory used by buffers */
  unsigned long totalswap; /* Total swap space size */
  unsigned long freeswap;  /* swap space still available */
  unsigned short procs;    /* Number of current processes */
  unsigned long totalhigh; /* Total high memory size */
  unsigned long freehigh;  /* Available high memory size */
  unsigned int mem_unit;   /* Memory unit size in bytes */
  char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding for libc5 */
};

sysinfo() is Linux specific, and the struct I included is for kernel versions 2.3.23 and later (assuming your platform is i386). Check the sysinfo(2) man page for details on the sysinfo struct for earlier versions of the kernel.