diff --git a/src/frontend/Makefile.am b/src/frontend/Makefile.am
index 94b9c859f..46000d289 100644
--- a/src/frontend/Makefile.am
+++ b/src/frontend/Makefile.am
@@ -121,6 +121,9 @@ libfte_la_SOURCES = \
     fourier.h   \
     gens.c      \
     gens.h      \
+    get_avail_mem_size.c     \
+    get_resident_set_size.c  \
+    get_phys_mem_size.c      \
     hpgl.c      \
     hpgl.h      \
     inp.c       \
diff --git a/src/frontend/get_avail_mem_size.c b/src/frontend/get_avail_mem_size.c
new file mode 100644
index 000000000..30acf4d6a
--- /dev/null
+++ b/src/frontend/get_avail_mem_size.c
@@ -0,0 +1,140 @@
+/*
+ * Author:  Holger Vogt
+ * License: 3-clause BSD License
+ * 
+ */
+
+#include "ngspice/ngspice.h"
+
+#if defined(_WIN32)
+#undef BOOLEAN
+#include <Windows.h>
+
+#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/param.h>
+#if defined(BSD)
+#include <sys/sysctl.h>
+#endif
+#if defined(__APPLE__) && defined(__MACH__)
+#import <mach/mach.h>
+#import <mach/mach_host.h>
+#endif
+#else
+#error "Unable to define getMemorySize( ) for an unknown OS."
+#endif
+
+
+/**
+ * Returns the size of available memory (RAM) in bytes.
+ */
+unsigned long long getAvailableMemorySize( )
+{
+#if defined(HAVE__PROC_MEMINFO)
+    /* Cygwin , Linux--------------------------------- */
+    /* Search for string "MemFree" */
+    FILE *fp;
+    char buffer[2048];
+    size_t bytes_read;
+    char *match;
+    unsigned long long mem_got;
+
+    if ((fp = fopen("/proc/meminfo", "r")) == NULL) {
+        perror("fopen(\"/proc/meminfo\")");
+        return 0L;
+    }
+
+    bytes_read = fread(buffer, 1, sizeof(buffer), fp);
+    fclose(fp);
+    if (bytes_read == 0 || bytes_read == sizeof(buffer))
+        return 0L;
+    buffer[bytes_read] = '\0';
+    match = strstr(buffer, "MemFree");
+    if (match == NULL) /* not found */
+        return 0L;
+    sscanf(match, "MemFree: %llu", &mem_got);
+    return mem_got * 1024;
+
+#elif defined(_WIN32)
+    /* Windows. ------------------------------------------------- */
+    MEMORYSTATUSEX status;
+    status.dwLength = sizeof(status);
+    GlobalMemoryStatusEx( &status );
+    return (size_t)status.ullAvailPhys;
+
+#elif defined(__APPLE__) && defined(__MACH__)
+
+    mach_port_t host_port;
+    mach_msg_type_number_t host_size;
+    vm_size_t pagesize;
+
+    host_port = mach_host_self();
+    host_size = sizeof(vm_statistics_data_t) / sizeof(integer_t);
+    host_page_size(host_port, &pagesize);
+
+    vm_statistics_data_t vm_stat;
+
+    if (host_statistics(host_port, HOST_VM_INFO, (host_info_t) &vm_stat,
+                &host_size) != KERN_SUCCESS) {
+        NSLog(@"Failed to fetch vm statistics");
+    }
+
+    /* Stats in bytes */
+/*    natural_t mem_used = (vm_stat.active_count + vm_stat.inactive_count +
+                                    vm_stat.wire_count) * pagesize; */
+    return vm_stat.free_count * pagesize;
+//    natural_t mem_total = mem_used + mem_free;
+
+#elif defined(__unix__) || defined(__unix) || defined(unix)
+    /* Linux/UNIX variants. ------------------------------------------- */
+    /* Prefer sysctl() over sysconf() except sysctl() HW_REALMEM and HW_PHYSMEM */
+
+#if defined(CTL_HW) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM64))
+    int mib[2];
+    mib[0] = CTL_HW;
+#if defined(HW_MEMSIZE)
+    mib[1] = HW_MEMSIZE;            /* OSX. --------------------- */
+#elif defined(HW_PHYSMEM64)
+    mib[1] = HW_PHYSMEM64;          /* NetBSD, OpenBSD. --------- */
+#endif
+    int64_t size = 0;               /* 64-bit */
+    size_t len = sizeof( size );
+    if ( sysctl( mib, 2, &size, &len, NULL, 0 ) == 0 )
+        return (size_t)size;
+    return 0L;          /* Failed? */
+
+#elif defined(_SC_AIX_REALMEM)
+    /* AIX. ----------------------------------------------------- */
+    return (size_t)sysconf( _SC_AIX_REALMEM ) * (size_t)1024L;
+
+#elif defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE)
+    /* FreeBSD, Linux, OpenBSD, and Solaris. -------------------- */
+    return (size_t)sysconf( _SC_PHYS_PAGES ) *
+        (size_t)sysconf( _SC_PAGESIZE );
+
+#elif defined(_SC_PHYS_PAGES) && defined(_SC_PAGE_SIZE)
+    /* Legacy. -------------------------------------------------- */
+    return (size_t)sysconf( _SC_PHYS_PAGES ) *
+        (size_t)sysconf( _SC_PAGE_SIZE );
+
+#elif defined(CTL_HW) && (defined(HW_PHYSMEM) || defined(HW_REALMEM))
+    /* DragonFly BSD, FreeBSD, NetBSD, OpenBSD, and OSX. -------- */
+    int mib[2];
+    mib[0] = CTL_HW;
+#if defined(HW_REALMEM)
+    mib[1] = HW_REALMEM;        /* FreeBSD. ----------------- */
+#elif defined(HW_PYSMEM)
+    mib[1] = HW_PHYSMEM;        /* Others. ------------------ */
+#endif
+    unsigned int size = 0;      /* 32-bit */
+    size_t len = sizeof( size );
+    if ( sysctl( mib, 2, &size, &len, NULL, 0 ) == 0 )
+        return (size_t)size;
+    return 0L;          /* Failed? */
+#endif /* sysctl and sysconf variants */
+
+#else
+    return 0L;          /* Unknown OS. */
+#endif
+}
diff --git a/src/frontend/get_phys_mem_size.c b/src/frontend/get_phys_mem_size.c
new file mode 100644
index 000000000..ef6c47b91
--- /dev/null
+++ b/src/frontend/get_phys_mem_size.c
@@ -0,0 +1,119 @@
+/*
+ * Author:   David Robert Nadeau
+ * Site:     http://NadeauSoftware.com/
+ * License:  Creative Commons Attribution 3.0 Unported License
+ *           http://creativecommons.org/licenses/by/3.0/deed.en_US
+ * Modified: Holger Vogt, 2019
+ */
+
+#include "ngspice/ngspice.h"
+
+#if defined(_WIN32)
+#undef BOOLEAN
+#include <Windows.h>
+
+#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/param.h>
+#if defined(BSD)
+#include <sys/sysctl.h>
+#endif
+
+#else
+#error "Unable to define getMemorySize( ) for an unknown OS."
+#endif
+
+
+
+/**
+ * Returns the size of physical memory (RAM) in bytes.
+ */
+unsigned long long getMemorySize()
+{
+#if defined(HAVE__PROC_MEMINFO)
+    /* Cygwin , Linux--------------------------------- */
+    FILE *fp;
+    char buffer[2048];
+    size_t bytes_read;
+    char *match;
+    unsigned long long mem_got;
+
+    if ((fp = fopen("/proc/meminfo", "r")) == NULL) {
+        perror("fopen(\"/proc/meminfo\")");
+        return 0;
+    }
+
+    bytes_read = fread(buffer, 1, sizeof(buffer), fp);
+    fclose(fp);
+    if (bytes_read == 0 || bytes_read == sizeof(buffer))
+        return 0;
+    buffer[bytes_read] = '\0';
+    /* Search for string "MemTotal" */
+    match = strstr(buffer, "MemTotal");
+    if (match == NULL) /* not found */
+        return 0;
+    sscanf(match, "MemTotal: %llu", &mem_got);
+    return mem_got * 1024L;
+
+#elif defined(_WIN32)
+    /* Windows. ------------------------------------------------- */
+    /* Use new 64-bit MEMORYSTATUSEX, not old 32-bit MEMORYSTATUS */
+    MEMORYSTATUSEX status;
+    status.dwLength = sizeof(status);
+    GlobalMemoryStatusEx( &status );
+    return (unsigned long long) status.ullTotalPhys;
+
+#elif defined(__unix__) || defined(__unix) || defined(unix) ||  \
+        (defined(__APPLE__) && defined(__MACH__))
+    /* UNIX variants. ------------------------------------------- */
+    /* Prefer sysctl() over sysconf() except sysctl() HW_REALMEM and HW_PHYSMEM */
+
+#if defined(CTL_HW) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM64))
+    int mib[2];
+    mib[0] = CTL_HW;
+#if defined(HW_MEMSIZE)
+    mib[1] = HW_MEMSIZE;            /* OSX. --------------------- */
+#elif defined(HW_PHYSMEM64)
+    mib[1] = HW_PHYSMEM64;          /* NetBSD, OpenBSD. --------- */
+#endif
+    int64_t size = 0;               /* 64-bit */
+    size_t len = sizeof( size );
+    if ( sysctl( mib, 2, &size, &len, NULL, 0 ) == 0 )
+        return (unsigned long long) size;
+    return 0L;          /* Failed? */
+
+#elif defined(_SC_AIX_REALMEM)
+    /* AIX. ----------------------------------------------------- */
+    return (unsigned long long) sysconf(_SC_AIX_REALMEM) * (size_t) 1024L;
+
+#elif defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE)
+    /* FreeBSD, Linux, OpenBSD, and Solaris. -------------------- */
+    return (unsigned long long) sysconf(_SC_PHYS_PAGES) *
+            (unsigned long long) sysconf(_SC_PAGESIZE);
+
+#elif defined(_SC_PHYS_PAGES) && defined(_SC_PAGE_SIZE)
+    /* Legacy. -------------------------------------------------- */
+    return (unsigned long long) sysconf(_SC_PHYS_PAGES) *
+            (unsigned long long) sysconf(_SC_PAGE_SIZE);
+
+#elif defined(CTL_HW) && (defined(HW_PHYSMEM) || defined(HW_REALMEM))
+    /* DragonFly BSD, FreeBSD, NetBSD, OpenBSD, and OSX. -------- */
+    int mib[2];
+    mib[0] = CTL_HW;
+#if defined(HW_REALMEM)
+    mib[1] = HW_REALMEM;        /* FreeBSD. ----------------- */
+#elif defined(HW_PYSMEM)
+    mib[1] = HW_PHYSMEM;        /* Others. ------------------ */
+#endif
+    unsigned long long size = 0; /* 32-bit */
+    size_t len = sizeof( size );
+    if ( sysctl( mib, 2, &size, &len, NULL, 0 ) == 0 )
+        return (unsigned long long) size;
+    return 0L;          /* Failed? */
+#endif /* sysctl and sysconf variants */
+
+#else
+    return 0L;          /* Unknown OS. */
+#endif
+}
diff --git a/src/frontend/get_resident_set_size.c b/src/frontend/get_resident_set_size.c
new file mode 100644
index 000000000..2ebfa7927
--- /dev/null
+++ b/src/frontend/get_resident_set_size.c
@@ -0,0 +1,125 @@
+/*
+ * Author:   David Robert Nadeau
+ * Site:     http://NadeauSoftware.com/
+ * License:  Creative Commons Attribution 3.0 Unported License
+ *           http://creativecommons.org/licenses/by/3.0/deed.en_US
+ * Modified: Holger Vogt, 2019
+ */
+
+#include "ngspice/ngspice.h"
+
+#if defined(_WIN32)
+#undef BOOLEAN
+#include <windows.h>
+#include <psapi.h>
+
+#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
+#include <unistd.h>
+#include <sys/resource.h>
+
+#if defined(__APPLE__) && defined(__MACH__)
+#include <mach/mach.h>
+
+#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
+#include <fcntl.h>
+#include <procfs.h>
+
+#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
+#include <stdio.h>
+
+#endif
+
+#else
+#error "Cannot define getPeakRSS( ) or getCurrentRSS( ) for an unknown OS."
+#endif
+
+
+/**
+ * Returns the peak (maximum so far) resident set size (physical
+ * memory use) measured in bytes, or zero if the value cannot be
+ * determined on this OS.
+ */
+unsigned long long getPeakRSS()
+{
+#if defined(HAVE_GETRUSAGE)
+    /* BSD, Linux, and OSX -------------------------------------- 
+     * not (yet) available with CYGWIN */
+    struct rusage rusage;
+    getrusage(RUSAGE_SELF, &rusage);
+#if defined(__APPLE__) && defined(__MACH__)
+    return (unsigned long long) rusage.ru_maxrss;
+#else
+    return (unsigned long long) (rusage.ru_maxrss * 1024L);
+#endif
+
+#elif defined(_WIN32)
+    /* Windows -------------------------------------------------- */
+    PROCESS_MEMORY_COUNTERS info;
+    GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
+        return (unsigned long long) info.PeakWorkingSetSize;
+
+#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
+    /* AIX and Solaris ------------------------------------------ */
+    struct psinfo psinfo;
+    int fd = -1;
+    if ( (fd = open( "/proc/self/psinfo", O_RDONLY )) == -1 )
+        return 0L;      /* Can't open? */
+    if ( read( fd, &psinfo, sizeof(psinfo) ) != sizeof(psinfo) )
+    {
+        close( fd );
+        return 0L;      /* Can't read? */
+    }
+    close( fd );
+        return (unsigned long long) (psinfo.pr_rssize * 1024L);
+
+#else
+    /* Unknown OS ----------------------------------------------- */
+    return 0L;          /* Unsupported. */
+#endif
+}
+
+
+
+
+
+/**
+ * Returns the current resident set size (physical memory use) measured
+ * in bytes, or zero if the value cannot be determined on this OS.
+ */
+unsigned long long getCurrentRSS( )
+{
+#if defined(_WIN32)
+    /* Windows -------------------------------------------------- */
+    PROCESS_MEMORY_COUNTERS info;
+    GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
+        return (unsigned long long) info.WorkingSetSize;
+
+#elif defined(__APPLE__) && defined(__MACH__)
+    /* OSX ------------------------------------------------------ */
+    struct mach_task_basic_info info;
+    mach_msg_type_number_t infoCount = MACH_TASK_BASIC_INFO_COUNT;
+    if ( task_info( mach_task_self( ), MACH_TASK_BASIC_INFO,
+        (task_info_t)&info, &infoCount ) != KERN_SUCCESS )
+        return 0L;      /* Can't access? */
+        return (unsigned long long) info.resident_size;
+
+//#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
+#elif defined(HAVE__PROC_MEMINFO)
+    /* Linux ---------------------------------------------------- */
+    unsigned long long rss = 0L;
+    FILE* fp = NULL;
+    if ( (fp = fopen( "/proc/self/statm", "r" )) == NULL )
+            return (unsigned long long) 0L; /* Can't open? */
+    if ( fscanf( fp, "%*s%llu", &rss ) != 1 )
+    {
+        fclose( fp );
+        return 0L;      /* Can't read? */
+    }
+    fclose( fp );
+        return rss * (unsigned long long) sysconf(_SC_PAGESIZE);
+
+#else
+    /* AIX, BSD, Solaris, and Unknown OS ------------------------ */
+    return (unsigned long long) 0L; /* Unsupported. */
+#endif
+}
diff --git a/src/frontend/resource.c b/src/frontend/resource.c
index 59ae13166..4b684cbab 100644
--- a/src/frontend/resource.c
+++ b/src/frontend/resource.c
@@ -6,10 +6,9 @@ Author: 1985 Wayne A. Christopher, U. C. Berkeley CAD Group
 /*
  * Resource-related routines.
  *
- * New operation systems information options added:
- * Windows 2000 and newer: Use GlobalMemoryStatusEx and GetProcessMemoryInfo
- * LINUX (and maybe some others): Use the /proc virtual file information system
- * Others: Use original code with sbrk(0) and some "ugly hacks"
+ * Time information is acquired here.
+ * Memory information is obtained in functions get_... for
+ * a large variety of current operating systems.
  */
 
 #include "ngspice/ngspice.h"
@@ -58,10 +57,6 @@ Author: 1985 Wayne A. Christopher, U. C. Berkeley CAD Group
 #include <unistd.h>
 #endif /* HAVE_WIN32 */
 
-/* Uncheck the following definition if you want to get the old usage information
-   #undef HAVE__PROC_MEMINFO
-*/
-
 static void printres(char *name);
 static void fprintmem(FILE *stream, unsigned long long memory);
 
@@ -72,25 +67,13 @@ static int get_sysmem(struct sys_mem *memall);
 struct sys_mem mem_t, mem_t_act;
 struct proc_mem mem_ng, mem_ng_act;
 
-#else
-static RETSIGTYPE fault(void);
-static void *baseaddr(void);
 #endif
 
-char *startdata;
-char *enddata;
-
 
 void
 init_rlimits(void)
 {
-#  if defined(HAVE_WIN32) || defined(HAVE__PROC_MEMINFO)
-    get_procm(&mem_ng);
-    get_sysmem(&mem_t);
-#  else
-    startdata = (char *) baseaddr();
-    enddata = sbrk(0);
-#  endif
+    ft_ckspace();
 }
 
 
@@ -138,12 +121,12 @@ com_rusage(wordlist *wl)
 
 
 /* Find out if the user is approaching his maximum data size.
-   If usage is withing 90% of total available then a warning message is sent
+   If usage is withing 95% of total available then a warning message is sent
    to the error stream (cp_err) */
 void
 ft_ckspace(void)
 {
-    unsigned long long usage, limit;
+    unsigned long long freemem, totalmem, usage, avail;
 
 #ifdef SHARED_MODULE
     /* False warning on some OSs, especially on Linux when loaded during runtime.
@@ -151,40 +134,20 @@ ft_ckspace(void)
     return;
 #endif
 
-#if defined(HAVE_WIN32) || defined(HAVE__PROC_MEMINFO)
-    get_procm(&mem_ng_act);
-    usage = mem_ng_act.size;
-    limit = mem_t.free;
-#else
-    static size_t old_usage = 0;
-    char *hi;
+    freemem = getAvailableMemorySize();
+    totalmem = getMemorySize();
+    usage = getCurrentRSS();
+    avail = usage + freemem;
 
-#ifdef HAVE_GETRLIMIT
-    struct rlimit rld;
-    getrlimit(RLIMIT_DATA, &rld);
-    if (rld.rlim_cur == RLIM_INFINITY)
-        return;
-    limit = rld.rlim_cur - (enddata - startdata); /* rlim_max not used */
-#else /* HAVE_GETRLIMIT */
-    /* SYSVRLIMIT */
-    limit = ulimit(3, 0L) - (enddata - startdata);
-#endif /* HAVE_GETRLIMIT */
-
-    hi = sbrk(0);
-    usage = (size_t) (hi - enddata);
-
-    if (usage <= old_usage)
+    if (totalmem == 0 || freemem == 0 || usage == 0)
         return;
 
-    old_usage = usage;
-#endif /* not HAS_WINGUI */
-
-    if ((double)usage > (double)limit * 0.9) {
+    if ((double)freemem < (double)totalmem * 0.05) {
         fprintf(cp_err, "Warning - approaching max data size: ");
         fprintf(cp_err, "current size = ");
         fprintmem(cp_err, usage);
         fprintf(cp_err, ", limit = ");
-        fprintmem(cp_err, limit);
+        fprintmem(cp_err, avail);
         fprintf(cp_err, "\n");
     }
 }
@@ -288,65 +251,25 @@ printres(char *name)
     }
 
     if (!name || eq(name, "space")) {
-# ifdef __APPLE__
-    #  ifdef HAVE_GETRUSAGE
-        int ret;
-        size_t usage = 0, limit = 0;
-        struct rusage ruse;
-        memset(&ruse, 0, sizeof(ruse));
-        ret = getrusage(RUSAGE_SELF, &ruse);
-        if (ret == -1)
-            perror("getrusage(): ");
-        usage = ruse.ru_maxrss;
-
-        size_t physmem;
-        size_t len = sizeof(physmem);
-        static int mib[2] = { CTL_HW, HW_MEMSIZE };
-
-        if (sysctl (mib, 2, &physmem, &len, NULL, 0) == 0)
-            limit = physmem;
-    # endif
-# else
-#  ifdef HAVE_GETRLIMIT
-        size_t usage = 0, limit = 0;
-        struct rlimit rld;
-        char *hi;
-
-        getrlimit(RLIMIT_DATA, &rld);
-        limit = rld.rlim_cur - (size_t)(enddata - startdata);
-        hi = (char*) sbrk(0);
-        usage = (size_t) (hi - enddata);
-#  else /* HAVE_GETRLIMIT */
-#    ifdef HAVE_ULIMIT
-        size_t usage = 0, limit = 0;
-        char *hi;
-
-        limit = ulimit(3, 0L) - (size_t)(enddata - startdata);
-        hi = sbrk(0);
-        usage = (size_t) (hi - enddata);
-#    endif /* HAVE_ULIMIT */
-#  endif /* HAVE_GETRLIMIT */
-# endif /* !__APPLE__ */
-
-#if defined(HAVE_WIN32) || defined(HAVE__PROC_MEMINFO)
-
-        get_procm(&mem_ng_act);
-        get_sysmem(&mem_t_act);
-
-        /* get_sysmem returns bytes */
+        unsigned long long mem = getMemorySize();
         fprintf(cp_out, "Total DRAM available = ");
-        fprintmem(cp_out, mem_t_act.size);
+        fprintmem(cp_out, mem);
         fprintf(cp_out, ".\n");
-
+        mem = getAvailableMemorySize();
         fprintf(cp_out, "DRAM currently available = ");
-        fprintmem(cp_out, mem_t_act.free);
+        fprintmem(cp_out, mem);
+        fprintf(cp_out, ".\n");
+        mem = getPeakRSS();
+        fprintf(cp_out, "Maximum ngspice program size = ");
+        fprintmem(cp_out, mem);
+        fprintf(cp_out, ".\n");
+        mem = getCurrentRSS();
+        fprintf(cp_out, "Current ngspice program size = ");
+        fprintmem(cp_out, mem);
         fprintf(cp_out, ".\n");
 
-        /* get_procm returns Kilobytes */
-        fprintf(cp_out, "Total ngspice program size = ");
-        fprintmem(cp_out, mem_ng_act.size);
-        fprintf(cp_out, ".\n");
 #if defined(HAVE__PROC_MEMINFO)
+        get_procm(&mem_ng_act);
         fprintf(cp_out, "Resident set size = ");
         fprintmem(cp_out, mem_ng_act.resident);
         fprintf(cp_out, ".\n");
@@ -371,15 +294,6 @@ printres(char *name)
            fprintmem(cp_out, all_memory.dt);
            fprintf(cp_out, ".\n"); */
 #endif  /* HAVE__PROC_MEMINFO */
-#else   /* HAS_WINGUI or HAVE__PROC_MEMINFO */
-        fprintf(cp_out, "Current dynamic memory usage = ");
-        fprintmem(cp_out, usage);
-        fprintf(cp_out, ",\n");
-
-        fprintf(cp_out, "Dynamic memory limit = ");
-        fprintmem(cp_out, limit);
-        fprintf(cp_out, ".\n");
-#endif
         yy = TRUE;
     }
 
diff --git a/src/frontend/resource.h b/src/frontend/resource.h
index 6d5f8c38d..21cad8912 100644
--- a/src/frontend/resource.h
+++ b/src/frontend/resource.h
@@ -6,6 +6,11 @@
 #ifndef ngspice_RESOURCE_H
 #define ngspice_RESOURCE_H
 
+extern size_t getMemorySize(void);
+extern size_t getPeakRSS(void);
+extern size_t getCurrentRSS(void);
+extern size_t getAvailableMemorySize(void);
+
 void init_rlimits(void);
 void init_time(void);
 void com_rusage(wordlist *wl);
diff --git a/visualc/vngspice.vcxproj b/visualc/vngspice.vcxproj
index bd62737a5..c2769c32c 100644
--- a/visualc/vngspice.vcxproj
+++ b/visualc/vngspice.vcxproj
@@ -1416,6 +1416,9 @@
     <ClCompile Include="..\src\frontend\fourier.c" />
     <ClCompile Include="..\src\frontend\ftesopt.c" />
     <ClCompile Include="..\src\frontend\gens.c" />
+    <ClCompile Include="..\src\frontend\get_phys_mem_size.c" />
+    <ClCompile Include="..\src\frontend\get_resident_set_size.c" />
+    <ClCompile Include="..\src\frontend\get_avail_mem_size.c" />
     <ClCompile Include="..\src\frontend\hcomp.c" />
     <ClCompile Include="..\src\frontend\help\help.c" />
     <ClCompile Include="..\src\frontend\help\provide.c" />