Within a single run, allow multiple plots with different names:

Add an increasing number to the id file name.

src/frontend/com_hardcopy.c

@@ -35,6 +35,8 @@ void com_hardcopy(wordlist *wl)
     int hc_button;
     int foundit;
 
+    static int n;
+
     if (!cp_getvar("hcopydev", CP_STRING, device, sizeof(device)))
         *device = '\0';
 
@@ -53,7 +55,8 @@ void com_hardcopy(wordlist *wl)
     }
     else {
         hc_button = 1;
-        fname = smktemp("hc");
+        fname = smktemp2("hc", n);
+        n++;
         tempf = TRUE;
         n_byte_fname = (strlen(fname) + 1) * sizeof *fname;
         if (!strcmp(devtype, "svg")) {

src/misc/mktemp.c

@@ -15,11 +15,12 @@ Copyright 1990 Regents of the University of California.  All rights reserved.
 #include <unistd.h>
 #endif
 
-
 #ifndef TEMPFORMAT
 #define TEMPFORMAT "temp%s%d"
 #endif
 
+#define TEMPFORMAT2 "%s%d_%d.tmp"
+
 char *
 smktemp(char *id)
 {
@@ -35,3 +36,21 @@ smktemp(char *id)
     }
     return tprintf(TEMPFORMAT, id, getpid());
 }
+
+
+char*
+smktemp2(char* id, int n)
+{
+    if (!id)
+        id = "sp";
+    const char* const home = getenv("HOME");
+    if (home) {
+        return tprintf("%s"TEMPFORMAT2, home, id, getpid(), n);
+    }
+    const char* const usr = getenv("USERPROFILE");
+    if (usr) {
+        return tprintf("%s\\"TEMPFORMAT2, usr, id, getpid(), n);
+    }
+    return tprintf(TEMPFORMAT2, id, getpid(), n);
+}
+

src/misc/mktemp.h

@@ -7,5 +7,6 @@
 #define ngspice_MKTEMP_H
 
 char * smktemp(char *id);
+char * smktemp2(char *id, int n);
 
 #endif