diskio.f_open_w() now also resets io channels back to defaults, like f_open() already did

compiler/res/prog8lib/cx16/diskio.p8

@@ -454,6 +454,8 @@ _end        jsr  cbm.READST
         ;    (for example, if it already exists). This is different than f_open()!
         ;    To be 100% sure if this call was successful, you have to use status()
         ;    and check the drive's status message!
+        ;    NOTE: the default output isn't yet set to this file, you must use reset_write_channel() to do this,
+        ;          if you're going to write to it yourself instead of using f_write()!
         return internal_f_open_w(filename, false)
     }
 
@@ -462,28 +464,6 @@ _end        jsr  cbm.READST
         return internal_f_open_w(filename, true)
     }
 
-    sub internal_f_open_w(str filename, bool open_for_seeks) -> bool {
-        f_close_w()
-        list_filename = filename
-        str modifier = ",s,?"
-        modifier[3] = 'w'
-        if open_for_seeks
-            modifier[3] = 'm'
-        cx16.r0L = strings.append(list_filename, modifier)   ; secondary 13 requires a mode suffix to signal we're writing/modifying
-        cbm.SETNAM(cx16.r0L, list_filename)
-        cbm.SETLFS(WRITE_IO_CHANNEL, drivenumber, WRITE_IO_CHANNEL)
-        void cbm.OPEN()             ; open 13,8,13,"filename"
-        if_cc {
-            if cbm.READST()==0 {
-                write_iteration_in_progress = true
-                return true
-            }
-        }
-        cbm.CLOSE(WRITE_IO_CHANNEL)
-        f_close_w()
-        return false
-    }
-
     sub f_write(uword bufferpointer, uword num_bytes) -> bool {
         ; -- write the given number of bytes to the currently open file
         ;    you can call this multiple times to append more data
@@ -523,6 +503,29 @@ no_mciout:
         }
     }
 
+    sub internal_f_open_w(str filename, bool open_for_seeks) -> bool {
+        f_close_w()
+        list_filename = filename
+        str modifier = ",s,?"
+        modifier[3] = 'w'
+        if open_for_seeks
+            modifier[3] = 'm'
+        cx16.r0L = strings.append(list_filename, modifier)   ; secondary 13 requires a mode suffix to signal we're writing/modifying
+        cbm.SETNAM(cx16.r0L, list_filename)
+        cbm.SETLFS(WRITE_IO_CHANNEL, drivenumber, WRITE_IO_CHANNEL)
+        void cbm.OPEN()             ; open 13,8,13,"filename"
+        if_cc {
+            if cbm.READST()==0 {
+                write_iteration_in_progress = true
+                cbm.CLRCHN()            ; reset default i/o channels
+                return true
+            }
+        }
+        cbm.CLOSE(WRITE_IO_CHANNEL)
+        f_close_w()
+        return false
+    }
+
 
     ; ---- other functions ----
 
@@ -892,6 +895,7 @@ io_error:
 
     sub exists(str filename) -> bool {
         ; -- returns true if the given file exists on the disk, otherwise false
+        ;    DON'T use this if you already have a file open with f_open!
         if f_open(filename) {
             f_close()
             return true

compiler/res/prog8lib/shared_cbm_diskio.p8

@@ -408,6 +408,8 @@ _end        jsr  cbm.READST
         ;    (for example, if it already exists). This is different than f_open()!
         ;    To be 100% sure if this call was successful, you have to use status()
         ;    and check the drive's status message!
+        ;    NOTE: the default output isn't yet set to this file, you must use reset_write_channel() to do this,
+        ;          if you're going to write to it yourself instead of using f_write()!
         f_close_w()
 
         cbm.SETNAM(strings.length(filenameptr), filenameptr)
@@ -416,6 +418,7 @@ _end        jsr  cbm.READST
         if_cc {
             if cbm.READST()==0 {
                 write_iteration_in_progress = true
+                cbm.CLRCHN()            ; reset default i/o channels
                 return true
             }
         }
@@ -614,6 +617,7 @@ io_error:
 
     sub exists(str filename) -> bool {
         ; -- returns true if the given file exists on the disk, otherwise false
+        ;    DON'T use this if you already have a file open with f_open!
         if f_open(filename) {
             f_close()
             return true

docs/source/libraries.rst

@@ -522,8 +522,13 @@ to see what's in there. (Note: slight variations for different compiler targets)
     It is possible that there are still small differences between HostFS and actual CBM DOS in the X16 emulator.
 
 .. note::
-    You can set the active disk drive number so it supports multiple drives,
+    You can set the active disk drive number, so it supports multiple drives, just one at a time.
-    but it does not support multiple open files at the same time.
+    It does not support reading from more than one file or writing to more than one file at a time.
+
+.. note::
+    If you want to print text to the screen, or do keyboard input, while reading or writing an open file is in progress,
+    you should use ``cbm.CLRCHN()`` before doing so. This resets the default i/o channels to screen and keyboard.
+    Diskio itself is smart enough to set them back to whatever is needed to continue reading/writing with the ``f_read`` or ``f_write`` routines.
 
 .. attention::
     Error handling is peculiar on CBM dos systems (C64, C128, cx16, PET). Read the

docs/source/todo.rst

@@ -1,8 +1,6 @@
 TODO
 ====
 
-Fix diskio (cx16, possibly other cbm targets too?) when opening write file , read file stops working
-
 add a -plain option to turn off text output coloring and unicode symbols in error messages (footguns)
 make a compiler switch to disable footgun warnings  -ignorefootguns
 

examples/test.p8

@@ -5,36 +5,26 @@
 
 main {
     sub start() {
-        txt.print("----with read 1:\n")
-        testread1()
-        txt.print("----with readline:\n")
-        testreadline()
-    }
 
-    sub testread1() {
+        if diskio.f_open("lines.txt") {
-        if not diskio.f_open("lines.txt")
+            defer diskio.f_close()
-            return
-        defer diskio.f_close()
 
-        str buffer = " "
+            if diskio.f_open_w("@:copy.txt") {
-        while 1==diskio.f_read(&buffer, 1) {
+                defer diskio.f_close_w()
-            txt.chrout(buffer[0])
+
+                str buffer = " "*80
+                ubyte length, status
+                do {
+                    length, status = diskio.f_readline(&buffer)
+                    cbm.CLRCHN()
+                    txt.print_uw(length)
+                    txt.nl()
+                    if length!=0 {
+                        if not diskio.f_write(buffer, length)
+                            return
+                    }
+                } until status!=0
+            }
         }
     }
-
-    sub testreadline() {
-        if not diskio.f_open("lines.txt")
-            return
-        defer diskio.f_close()
-
-        str buffer = " "*80
-        ubyte length, status
-        do {
-            length, status = diskio.f_readline(&buffer)
-            if length!=0 {
-                txt.print(buffer)
-                txt.nl()
-            }
-        } until status!=0
-    }
 }