Clean up show/hide/and add get visibility method on Windows

README.md

@@ -311,12 +311,26 @@ xx, yy = mxcall(:meshgrid, 2, x, y)
 
 ``mxcall`` puts the input arguments to the MATLAB workspace (using mangled names), evaluates the function call in MATLAB, and retrievs the variable from the MATLAB session. This function is mainly provided for convenience. However, you should keep in mind that it may incur considerable overhead due to the communication between MATLAB and Julia domain.
 
-#### Viewing the MATLAB Session
+#### Viewing the MATLAB Session (Windows only)
 
-To open an interactive window for the MATLAB session, use the command `show_msession()`. To hide the window, use `hide_msession()`. Note that closing this window will result in an error, so it is advised that one uses the `hide_msession()` command instead.
+To open an interactive window for the MATLAB session, use the command `show_msession()` and to hide the window, use `hide_msession()`. *Warning: manually closing this window will result in an error or result in a segfault; it is advised that you only use the `hide_msession()` command to hide the interactive window.*
 
 Note that this feature only works on Windows.
 
+```julia
+# default
+show_msession() # open the default MATLAB session interactive window
+get_msession_visiblity() # get the session's visibility state
+hide_msession() # hide the default MATLAB session interactive window
+
+# similarily
+s = MSession()
+show_msession(s)
+get_msession_visiblity(a)
+hide_msession(s)
+```
+
+
 #### Advanced use of MATLAB Engines
 
 This package provides a series of functions for users to control the communication with MATLAB sessions.

src/MATLAB.jl

@@ -31,9 +31,11 @@ export MSession, MatFile,
        eval_string, get_mvariable, get_variable, put_variable, put_variables,
        variable_names, read_matfile, write_matfile,
        mxcall,
-       @mput, @mget, @matlab, @mat_str,
-       show_msession, hide_msession
+       @mput, @mget, @matlab, @mat_str
 
+if is_windows()
+    export show_msession, hide_msession, get_msession_visiblity
+end
 
 # exceptions
 type MEngineError <: Exception
@@ -65,6 +67,7 @@ function __init__()
     eng_open[]          = engfunc(:engOpen)
     eng_close[]         = engfunc(:engClose)
     eng_set_visible[]   = engfunc(:engSetVisible)
+    eng_get_visible[]   = engfunc(:engGetVisible)
     eng_output_buffer[] = engfunc(:engOutputBuffer)
     eng_eval_string[]   = engfunc(:engEvalString)
     eng_put_variable[]  = engfunc(:engPutVariable)

src/engine.jl

@@ -90,18 +90,25 @@ function close_default_msession()
     return nothing
 end
 
-function show_msession(m::MSession = get_default_msession())
-    ret = ccall(eng_set_visible[], Cint, (Ptr{Void}, Cint), m, 1)
-    ret != 0 && throw(MEngineError("failed to show MATLAB engine session (err = $ret)"))
-    return nothing
-end
+if is_windows()
+    function show_msession(m::MSession = get_default_msession())
+        ret = ccall(eng_set_visible[], Cint, (Ptr{Void}, Cint), m, 1)
+        ret != 0 && throw(MEngineError("failed to show MATLAB engine session (err = $ret)"))
+        return nothing
+    end
 
-function hide_msession(m::MSession = get_default_msession())
-    ret = ccall(eng_set_visible[], Cint, (Ptr{Void}, Cint), m, 0)
-    ret != 0 && throw(MEngineError("failed to hide MATLAB engine session (err = $ret)"))
-    return nothing
-end
+    function hide_msession(m::MSession = get_default_msession())
+        ret = ccall(eng_set_visible[], Cint, (Ptr{Void}, Cint), m, 0)
+        ret != 0 && throw(MEngineError("failed to hide MATLAB engine session (err = $ret)"))
+        return nothing
+    end
 
+    function get_msession_visiblity(m::MSession = get_default_msession())
+        vis = Ref{Cint}(true)
+        ccall(eng_get_visible[], Int, (Ptr{Void}, Ptr{Cint}), m, vis)
+        return vis[] == 1 ? true : false
+    end
+end
 
 ###########################################################
 #

src/init.jl

@@ -9,6 +9,7 @@ const libmat = Ref{Ptr{Void}}()
 const eng_open          = Ref{Ptr{Void}}()
 const eng_close         = Ref{Ptr{Void}}()
 const eng_set_visible   = Ref{Ptr{Void}}()
+const eng_get_visible   = Ref{Ptr{Void}}()
 const eng_output_buffer = Ref{Ptr{Void}}()
 const eng_eval_string   = Ref{Ptr{Void}}()
 const eng_put_variable  = Ref{Ptr{Void}}()
@@ -84,7 +85,7 @@ const mx_set_field             = Ref{Ptr{Void}}()
 const mx_get_field_bynum       = Ref{Ptr{Void}}()
 const mx_get_fieldname         = Ref{Ptr{Void}}()
 
-const mx_get_string = Ref{Ptr{Void}}(0)
+const mx_get_string = Ref{Ptr{Void}}()
 
 # load I/O mat functions