updated file io test to avoid crash

src/amsstring4/amsstring4_class.cpp

@@ -133,7 +133,7 @@ namespace ams
     {
       int ret = amsstring_success;
       ams_chartype *newcstring = NULL;
-      int I;
+      int I = 0;
 
       _newlen = (_newlen<0) ? 0 : _newlen;
 
@@ -145,6 +145,10 @@ namespace ams
         return ret;
       }
 
+      for(I=0;I<(_newlen+1);I++) //init entire string to '\0' - slower, but valgrind complains less
+      {
+        newcstring[I] = (ams_chartype) '\0';
+      }
       if(cstring!=NULL)
       {
         for(I=0;I<(_newlen+1) && I<(length+1);I++)
@@ -152,10 +156,10 @@ namespace ams
           newcstring[I] = cstring[I];
         }
       }
-      for(I=length;I<(_newlen+1);I++)
-      {
-        newcstring[I] = (ams_chartype) '\0';
-      }
+      // for(I=length;I<(_newlen+1);I++) //init only new portion of string to '\0' - valgrind complains?
+      // {
+      //   newcstring[I] = (ams_chartype) '\0';
+      // }
 
       newcstring[_newlen] = '\0';
 
@@ -1402,7 +1406,11 @@ namespace ams
     {
       const int BUFFSZ = 8000;
       char buff[BUFFSZ];
-      int N;
+      int N = 0;
+
+      int I = 0;
+      for(I=0;I<BUFFSZ;I++) buff[I] = '\0'; //this shuts valgrind up about uniitialized values
+
       if(fp!=NULL && s!=NULL)
       {
         if(!feof(fp))

src/amsstring4/amsstring4_tests1.cpp

@@ -429,6 +429,12 @@ namespace ams
     
         fp = fopen("./ref/0p375_hexbolt.scad","r");
         fp2 = fopen("./ref/testrewrite.scad","w+");
+
+        if(fp==NULL || fp2==NULL)
+        {
+            printf("amsstring4_test_freadwrite: could not open test files, make sure you're executing this from the project root.\n");
+            return;
+        }
     
         I = 0;
         while(!feof(fp))

src/main.cpp

@@ -20,7 +20,7 @@ int main(int argc, char* argv[])
     amsstring4_test_strip();
     amsstring4_test_freadwrite();
 
-    amsstring4_test_concatenation_operators();
+    amsstring4_test_concatenation_operators(); //segfault on Debian11?
     
     return ret;
 }