Update: "make" instead of "make linux32" should also work. I believe the "linux32" target came 
from some special case at TRIUMF for some FPGA embedded linux, which is not applicable for 
the Raspberry Pi.

Note that the build process has to be initiated on the Raspberry Pi, NOT a host PC.

Stefan

Please note that 

"make cmake" / "make cmake3"

is an abbreviation for the "normal" cmake command chain. Users familiar with cmake can also do the standard command chain:

mkdir build
cd build
cmake ..
make
make install


- Stefan

> We are happy to the midas release "midas-2019-06" with the build system implemented in cmake and the midas, mxml and mscb 
> projects switched to C++.
> 
> Changes since midas-2019-03:
> 
> minor bug fixes
> switch of midas build to c++ with c++ linkage (no "extern C")
> switch of midas build to cmake
> removal of $(OS_DIR) from the midas library and bin paths (use $MIDASSYS/lib instead of $MIDASSYS/linux/lib)
> mxml and mscb are implemented as git submodules
> 
> Please review the following guide to update midas from previous release midas-2019-03 or older.
> 
> Update the code:
> 
> git checkout develop
> git pull
> git checkout feature/midas-2019-06
> git pull
> git submodule update --init # this will checkout correct versions of mxml and mscb
> make clean
> make cclean
> rm -rf linux/bin
> rm -rf linux/lib
> rmdir linux
> make cmake3 # or "make cmake" on ubuntu and macos
> ls -l bin/odbedit bin/mlogger
> 
> Update experiment environment:
> 
> - change PATH from $MIDASSYS/linux/bin to $MIDASSYS/bin
> 
> Cleanup unneeded stuff:
> 
> - remove $HOME/packages/mxml (new location $MIDASSYS/mxml)
> - remove $HOME/packages/mscb (new location $MIDASSYS/mscb)
> 
> Update experiment frontend build:
> 
> - change Makefile to remove $(OS_DIR) from library search path ($MIDASSYS/linux/lib becomes $MIDASSYS/lib)
> - change Makefile to set mxml include path from $MIDASSYS/../mxml to $MIDASSYS/mxml (to avoid including the wrong 
> version of mxml/strlcpy.h)
> - update frontend code to use mfe.h and build as C++, see https://midas.triumf.ca/elog/Midas/1526
> 
> K.O.

Note that the example experiment compiles a simple example frontend and a root-based analyzer. If you don't have 
ROOT installed, you of course cannot compile the analyzer. If you don't need the analyzer, remove it from the 
Makefile/CMakeLists.txt

It's not clear to me why the frontend did not compile on our server machine. You did not post the command how you 
initiated the build. Note that there are now two parallel build schemes: the traditional Makefile and the new 
CMakeFiles.txt. We try to maintain both of them, so you have to specify which one you use when you get an error.

I realize now that the CMakeLists.txt in the experiment example directory builds nicely under midas, but when you move 
it to another directory and extract it from the normal build scheme it breaks. I rewrote the CMakeLists.txt now that it 
looks for MIDASSYS and also build at different locations. Do

cd $HOME/online
cp $MIDASSYS/examples/experiment/* .
mkdir build
cd build
cmake ..
make

and it should work. Of course first pull the current develop version.

Stefan

Sure some existing scripting languages can be used, but they fall short of a few important items in larger experiments:

- they are typically run from a local terminal in the counting house. A remote observer of the experiment has no idea which script is running and at which state it is.

- if DAQ crashes during a script or is aborted, it has to be restarted from the beginning. If you run a sequence of let's say 100 runs taking 8 hours, and on run #98 something goes wrong, you are screwed if you have to start at run #1 again.

This are the main reasons why I developed the midas sequencer. Having everything web-based, everybody can watch remotely how far the sequence progressed. If the whole DAQ crashes, the sequence resumes from the crash point, not from the beginning. This is by saving the current state into the ODB. So even if the sequencer itself is stopped and restarted, that still works.

I agree that the MSL is missing a few calculations, and I was just waiting to get a few specific requests. I will either add new functions such as basic calculations like adding and subtracting variables, or I will create a way to call an external shell like bash to do calculations. I put this high on my todo list.

Stefan

> Yes, this has been the way to do it for years...

Calling odbedit -c ... ist certainly not the most effective way, but it works. I just tried on my Mac and found that I can call odbedit about 150 times per second. So not so bad if you have a limited operations to perform.

Stefan

The bug has been fixed. It was actually in the mxml library. So you have to go to the midas/mxml 
subdirectory and update that one via "git pull origin master".

Stefan

> Hi,
> the subject line describes the project already
> Suppose you have a file foo.msl. Somewhere in the file, you have the line 
> INCLUDE bar.msl
> 
> Once you click save in the sequencer page, mhttpd crashes:
> $ mhttpd
> free(): double free detected in tcache 2
> [1]    27590 abort (core dumped)  mhttpd
> 
> 
> GDB helps shed some light on the problem:
> 
> #0  0x00007ffff76b057f in raise () from /lib64/libc.so.6
> #1  0x00007ffff769a895 in abort () from /lib64/libc.so.6
> #2  0x00007ffff76f39d7 in __libc_message () from /lib64/libc.so.6
> #3  0x00007ffff76fa2ec in malloc_printerr () from /lib64/libc.so.6
> #4  0x00007ffff76fbdf5 in _int_free () from /lib64/libc.so.6
> #5  0x00000000004b8b41 in mxml_parse_entity (buf=buf@entry=0x7fffffffc2c8,
> file_name=file_name@entry=0x7fffffffc710
> "/home/luk/packages/mutrig_daq/online/foo.xml",
>             error=error@entry=0x7fffffffcd24 "XML read error in file
> \"/home/luk/packages/mutrig_daq/online/foo.xml\", line 2: bar.msl.xml is
> missing", error_size=error_size@entry=256,
>                 error_line=error_line@entry=0x7fffffffce24) at ../mxml/mxml.c:1996
> #6  0x00000000004b966d in mxml_parse_file
> (file_name=file_name@entry=0x7fffffffc710
> "/home/luk/packages/mutrig_daq/online/foo.xml",
>             error=error@entry=0x7fffffffcd24 "XML read error in file
> \"/home/luk/packages/mutrig_daq/online/foo.xml\", line 2: bar.msl.xml is
> missing", error_size=error_size@entry=256,
>                 error_line=error_line@entry=0x7fffffffce24) at ../mxml/mxml.c:2041
> #7  0x000000000041d9c2 in init_sequencer () at src/mhttpd.cxx:14321
> #8  0x000000000040c2b6 in main (argc=<optimized out>, argv=<optimized out>) at
> src/mhttpd.cxx:18028
> 
> Cheers
> Lukas
> 
> P. S. This problem reminds me of the old joke: A man goes to his doctor and says
> "Doc, it hurts when I do this" to which the doctor replies "Then don't do that".
> However, I think, mhttpd should not crash even if you're not supposed to include
> non-existent scripts in msequencer.

> You can confirm that you are linking against the correct ROOT by running cmake with VERBOSE=1
> and examine the linker command line to see what library link path is specified for ROOT.

Actually you don't call cmake with the verbose flag but specify it during the make phase

$ make VERBOSE=1

to see the command lines.

Stefan

> - this will activate the mhttpd password protection, so one would have to define a username and password 
> in the .htdigest file (this is done by the mongoose web server library).

Actually I'm thinking since a while to have user-level access to mhttpd, similarly to elog. Each user has to log in with a unique username/password. After some time of inactivity, you're logged out. This would have 
the advantage that one knows who is active where, like when using the chat functionality in mhttpd. Or who started/stopped a run etc. This might not be necessary for simple local installations, but if you have 20 
people controlling an experiment from three different continents simultaneously, this could be beneficial. Using the elog authentication libraries, one could even forward the login process to LDAP or KERBEROS, 
so you could log in with out institutional account, and don't have to remember an additional password.

Just some food for thought.

Stefan

Did you include mfe.h as written in elog:1526 ?

Stefan

Have you left any "extern C" in your frontend program or in any of the used header file. Seems 
like the linker cannot find the poll_event in your frontend code. If it's there, but it's compiled 
with C calling (instead of C++), the name mangling causes it to be invisible to the linker. That 
usually happens if there is somewhere

extern C {
  INT poll_event();
  ... 
}

while it is NOT defined as "extern C" in mfe.h which is used by mfe.cxx.

Stefan

> > Did you include mfe.h as written in elog:1526 ?
> > 
> > Stefan
> 
> 
> Yes I did
> 
> this is my include 
> 
> #include <stdio.h>
> #include <string.h>
> #include <assert.h>
> #include <math.h>
> #include <pthread.h>
> 
> 
> #include "midas.h"
> #include "mscb.h"
> #include "multi.h"
> #include "mscbdev.h"
> #include "mfe.h"
> 
> (I attach my dummy fe)
> 
> What confuses me is that I can compile examples/experiment/ if I copy that to a 
> fresh dir.
> 
> I also copied the CMakeLists from the example:
> 
> #
> # cmake for the muX software
> #
> cmake_minimum_required(VERSION 3.3)
> 
> project(muX)
> 
> #
> # find midas installation, from CMakeLists in examples/experiment
> #
> set(MIDAS_DIR $ENV{MIDASSYS})
> message("MIDAS dir: " ${MIDAS_DIR})
> if (NOT EXISTS $ENV{MIDASSYS})
>   message(FATAL_ERROR "Environment variable $MIDASSYS not defined, aborting.")
> endif()
> 
> set(INC_PATH ${MIDAS_DIR}/include ${MIDAS_DIR}/mxml ${MIDAS_DIR}/mscb/include 
> ${MIDAS_DIR}/drivers/class ${MIDAS_DIR}/drivers/device)
> link_directories($ENV{MIDASSYS}/lib)
> 
> # enable certain compile warnings
> add_compile_options(-Wall -Wformat=2 -Wno-format-nonliteral -Wno-strict-
> aliasing -Wuninitialized -Wno-unused-function)
> 
> set(LIBS -lpthread -lutil -lrt) 
> 
> 
> add_executable(sc_fe_mini sc_fe_mini.cpp)
> target_include_directories(sc_fe_mini PRIVATE ${INC_PATH})
> target_link_libraries(sc_fe_mini mfe midas ${LIBS})

> as a side comment, not all drivers are c++ compatible yet (e.g. mscbvr), so changes needed are small 

Right. We recently switched the whole midas to c++, but we could not cover all drivers. Most of them just need some type 
casting to compile under c++. I got already patches from several people which I'm happy to merge in. If you got mscbhvr 
or any other driver compile under c++, please send me the diff.

Stefan

> Would it be possible to add something like the following?
>  343 if (!isdigit(value1_var[i]) && value1_var[i] != '.')
>  344          break;

Actually isdigit() is completely wrong here, because it also fails the minus sign and the 'E' exponent, like in -1.2E-3 

So I changed it to strchr("0123456789.+-Ee", var[i]) which should cover this case. If you put 1.2.3, it takes it as 1.2. 

Stefan

> 
> Ok, so the detail that I missed was that the dummy functions
> 
> INT poll_event(INT source[], INT count, BOOL test)
> {
>    return 1;
> };
> 
> as shown in some of the older examples, work when you set
> 
> INT poll_event(INT source, INT count, BOOL test)
> {
>    return 1;
> };

If you would have read elog:1526 more carefully (point a4) you would have saved yourself a lot of time.

Stefan

Today I fixed a long-annoying problem. We have in each front-end an equipment structure 
which defined the event id, event type, readout frequency etc. This is mapped to the ODB 
subtree

/Equipment/<name>/Common

In the past, the ODB setting took precedence over the frontend structure. We defined this 
like 25 years ago and I forgot what the exact reason was. It causes however many people 
(including myself) to fall into this trap: You change something in the front-end EQUIPMENT 
structure, you restart the front-end, but the new setting does not take effect since the 
(old) ODB value took precedence. After some debugging you find out that you have to both 
change the EQUIPMENT structure (which defines the default value for a fresh ODB) and the 
ODB value itself.

So I changed it in the current develop tree that the front-end structure takes precedence. 
You still have a hot-link, so if you want to change anything while the front-end is running 
(like the readout period), you can do that in the ODB and it takes effect immediately. But 
when you start the front-end the next time, the value from the EQUIPMENT structure is 
taken again. So please be aware of this new feature.

Happy BC day,
Stefan

Hi Thomas,

the change only affects Eqipment/<name>/common not the Equipment/<name>/Settings. 

The Common subtree is still hot-linked into the frontend, so when running things can be changed if needed. This mainly concerns the readout period of periodic events. 
Sometimes you want to change this quickly without restarting the frontend. Changing the other settings are kind of dangerous. If you change the ID of an event on the fly
you won't be able to analyze your data. So having this read-only in the ODB might be a good idea (you still need it in the ODB for the status page), except for the values
you want to change (like the readout period). 

Let's see what other people have to say.

Stefan

> Hi Stefan,
> 
> This change does not sound like a good idea to me.  I think that this change will cause just as much confusion as before; probably more since you are changing established behaviour.
> 
> It is common that MIDAS frontends usually have a Settings directory in the ODB where details about the frontend behaviour are set.  The Settings directory might get initialized from strings in the frontend code, but after initialization the Settings in the ODB have precedence and define how the frontend will behave.  Indeed, most of my custom webpages are designed to control my frontend programs through their Settings ODB tree.
> 
> So you have created a situation where Frontend/Settings in the ODB has precedence and is the main place for changing frontend behaviour; but Frontend/Common in the ODB is essentially meaningless and will get overwritten the next time the frontend restarts.  That seems likely to confuse people. 
> 
> If you really want to make this change I suggest that you delete the Frontend/Common directory entirely; or make it read-only so that people aren't fooled into changing it.
> 
> Thomas 
> 
> 
> 
> > Today I fixed a long-annoying problem. We have in each front-end an equipment structure 
> > which defined the event id, event type, readout frequency etc. This is mapped to the ODB 
> > subtree
> > 
> > /Equipment/<name>/Common
> > 
> > In the past, the ODB setting took precedence over the frontend structure. We defined this 
> > like 25 years ago and I forgot what the exact reason was. It causes however many people 
> > (including myself) to fall into this trap: You change something in the front-end EQUIPMENT 
> > structure, you restart the front-end, but the new setting does not take effect since the 
> > (old) ODB value took precedence. After some debugging you find out that you have to both 
> > change the EQUIPMENT structure (which defines the default value for a fresh ODB) and the 
> > ODB value itself.
> > 
> > So I changed it in the current develop tree that the front-end structure takes precedence. 
> > You still have a hot-link, so if you want to change anything while the front-end is running 
> > (like the readout period), you can do that in the ODB and it takes effect immediately. But 
> > when you start the front-end the next time, the value from the EQUIPMENT structure is 
> > taken again. So please be aware of this new feature.
> > 
> > Happy BC day,
> > Stefan

After some internal discussion, I decided to undo my previous change again, in order not to break existing habits. Instead, I created a new function

set_odb_equipment_common(equipment, name);

which should be called from frontend_init() which explicitly copies all data from the equipment structure in the front-end into the ODB.

Stefan

Each CMakeLists.txt should specify which version of CMake it requires. The MIDAS CMakeLists.txt requires CMake 3.1 or later. 
We deliberately stayed away from fancy cutting edge CMake features in order to make midas easier to compile. On top of that,
midas is a much simpler package compared to root, so things are not so complicated.

Stefan

I just tried CMake 3.1.0 and it worked with midas. So I believe all versions between 3.1.0 and 3.6.1 are ok.

Actually playing around with different versions I realized that 3.0.0 is also ok, so I changed the requirement of midas down to 3.0

Stefan

> Lacking any ideas for improvements, I vote for the status quo. (plus a review of the documentation to ensure we have clearly
> written up what each entry in "common" does and whether the user is permitted to edit it in odb).

I agree with that.

Stefan

During my visit at TRIUMF we rewrote the history plotting functionality of midas. Instead of 
static GIF images, we have now interactive JavaScript panels where we can scroll, zoom, 
inspect values and much more (example is attached). We are now in a state where this is still 
work in progress, but already at this stage it might be useful for others to report any 
feedback.

Simply upgrade the the newest develop branch of midas, and you will see two menu items 
"OldHistory" which is the old system and "History" which is the new system. In the new 
system, you can drag with the mouse to scroll, use the mouse wheel to zoom in and out the 
time axis, and hover with your mouse over data points to see its value. If you zoom out, 
old data is loaded automatically in the background.

Following items are planned, but not yet implemented:

- Printing of run markers as in the old history

- Delete old data in the buffer to limit memory consumption if the browser window is 
   open for very long (weeks)

- Implement time interval selector (clock icon, select "last day", "last 8 hours" etc.)

- New settings dialog as a floating dialog box. At the moment, the setting page of the 
   old history system is used

- Export / Printing / Sending to ELOG any history plot

- Implement a formula for plotting data, such as "y = 12 * (x-14) +32". This will replace 
   the old "offset" and "factor" and is more flexible. The formula can be passed directly 
   to the JavaScript engine and will be executed on the web page. It should be also 
   possible to combine different channels, like the difference of two history values.

- Determine the number of digits for variable display from the axis limits. Like if a value 
   changes between 520001 and 520002 only, we need more digits than the usual 6.

Many of these things will be implemented in the next weeks. If you have any more idea 
or find some bugs, please report back to me.

Best,
Stefan for the midas team