How can you get how much memory is available using c program?

Answer 1

You don't say whether you mean physical memory or virtual memory. Regardless, there is no portable method given that memory management is system-specific. However, the system should provide some means of giving you the information you need. The following example works on Windows and Linux:

#ifdef WIN32 #include <windows.h>

unsigned long long getTotalSystemMemory()

{

MEMORYSTATUSEX status;

status.dwLength = sizeof(status);

GlobalMemoryStatusEx(&status);

return status.ullTotalPhys;

}

#else // UNIX...

#include <unistd.h>

unsigned long long getTotalSystemMemory()

{

long pages = sysconf(_SC_PHYS_PAGES);

long page_size = sysconf(_SC_PAGE_SIZE);

return pages * page_size;

}

#endif

Answer 2

There is no portable means of doing so because different operating systems manage memory in different ways.

In Windows, use the following code:

#include "windows.h"

#include "psapi.h"

PROCESS_MEMORY_COUNTERS_EX pmc;

GetProcessMemoryInfo (GetCurrentProcess(), (PROCESS_MEMORY_COUNTERS*)&pmc, sizeof(pmc));

// pmc.WorkingSetSize tells us how much physical RAM is currently consumed by this process.

// pmc.PrivateUsage tells us how much virtual memory is currently consumed by this process.

In Linux, use the following code:

#include "stdlib.h"

#include "stdio.h"

#include "string.h"

int parseLine(char*); // forward declaration (used by getWorkingSize() and getPrivateUsage())

// tells us how much physical RAM is currently consumed by this process (in KB)

int getWorkingSetSize(){

FILE* file = fopen("/proc/self/status", "r");

int result = -1;

char line[128];

while (fgets(line, 128, file) != NULL){

if (strncmp(line, "VmSize:", 7) == 0){

result = parseLine(line);

break;

}

}

fclose(file);

return result;

}

// tells us how much virtual memory is currently consumed by this process (in KB)

int getPrivateUsage(){

FILE* file = fopen("/proc/self/status", "r");

int result = -1;

char line[128];

while (fgets(line, 128, file) != NULL){

if (strncmp(line, "VmRSS:", 6) == 0){

result = parseLine(line);

break;

}

}

fclose(file);

return result;

}

int parseLine(char* line){

int i = strlen(line);

const char* p = line;

while (*p <'0' *p > '9') p++;

line[i-3] = '\0';

i = atoi(p);

return i;

}