add an option to close all files

src/io.c

@@ -762,12 +762,24 @@ void myclose(void) /* close the specified stream */
 #endif
   
   s=(int)pop(stNUMBER)->value;
+  if (s == -2){
+  	for(s=1;s<FOPEN_MAX-4;s++) {
+  		if (stream_modes[s]!=smCLOSED) {
+  			streams[s]=NULL;
+  			stream_modes[s]=smCLOSED;
+      	}
+    }
+    return;
+  }
+  
   if (abs(s)==STDIO_STREAM || badstream(s,0)) return;
   if (stream_modes[s]==smCLOSED) {
     sprintf(string,"stream %d already closed",s);
     error(WARNING,string);
     return;
   }
+  
+	
   if (s==lprstream) {
 #ifdef UNIX
     pclose(lineprinter);

yab-IDE/data/Help_En.dat

@@ -3211,18 +3211,26 @@ close -- close a file, which has been opened before
 Synopsis: 
 close filenum 
 close # filenum
+close -2
+close #-2 
 
 Description:
+
 The close-command closes an open file. You should issue this command as soon as you are done with reading from or writing to a file.
 
+close -2 closes all open files. 
 Example:
+
+all = -2
 open "my.data" for reading as 1 
 input #1 a 
 print a 
-close 1 
+close all 
+
 Explanation:
 
-This program opens the file "my.data", reads a number from it, prints this number and closes the file again.
+This program opens the file "my.data", reads a number from it, prints this number and then closes all files.
+
 
 
 Related: open