DOC: Change error message for lkt when unable to connect to lektord + update README

Be more explicit about the need for lektord to be launched before using
the lkt client.

Also update the readme:
- add the update procedure
- 80 col formated text

README.md

@@ -19,10 +19,11 @@ A Karaoke player made to replace the old bash scripts on Sakura.
 
 ### Prerequisites
 
-- [autotools](https://www.gnu.org/software/autoconf/), libtool, autoconf, automake, etc
+- [autotools](https://www.gnu.org/software/autoconf/), libtool,
+  autoconf, automake, etc
 - a C compiler with C11 support
-- the [sqlite3](https://www.sqlite.org/) development library, version 3.31.0 or newer for
-  [generated columns](https://www.sqlite.org/gencol.html) support
+- the [sqlite3](https://www.sqlite.org/) development library, version
+  3.31.0 or newer for [generated columns](https://www.sqlite.org/gencol.html) support
 - a POSIX.1-2008 compatible system (i.e. not MS Windows)
 
 For the module sdl2, you will need the folowing prerequisites:
@@ -41,36 +42,40 @@ To build Klkt, you will need:
 - qmake and Qt5 developpement libraries (Qt5Core Qt5Gui Qt5Network Qt5Widgets)
 - don't forget the qt5dxcb-plugin (xcb plugin for qt5) when compiling
 
-You will also need the following executables, with their path setted in the configuration file:
+You will also need the following executables, with their path setted in
+the configuration file:
 
 - mkvpropedit from [mkvtoolnix](https://gitlab.com/mbunkus/mkvtoolnix)
 - the bourn shell again: [bash](https://git.savannah.gnu.org/cgit/bash.git)
 - the command line tool xxd, is distributed in the
   [vim](https://www.archlinux.org/packages/extra/x86_64/vim/) and
-  [gvim](https://www.archlinux.org/packages/extra/x86_64/gvim/) packages on archlinux, seems to be
-  distributed in its own package on debian: [xxd](https://packages.debian.org/sid/xxd)
+  [gvim](https://www.archlinux.org/packages/extra/x86_64/gvim/) packages
+  on archlinux, seems to be distributed in its own package on debian:
+  [xxd](https://packages.debian.org/sid/xxd)
 
-If you use the configure with the `--with-depends` option (needed on debian 10), you will need the
-following dependencies:
+If you use the configure with the `--with-depends` option (needed on
+debian 10), you will need the following dependencies:
 
-- the [curl](https://curl.haxx.se/) command line utility. It can be replaced by the wget command
-  line utility.
-- the [wget](https://www.gnu.org/software/wget/) command line utility. Can be replaced by curl
-  command line utility.
+- the [curl](https://curl.haxx.se/) command line utility. It can be
+  replaced by the wget command line utility.
+- the [wget](https://www.gnu.org/software/wget/) command line utility.
+  Can be replaced by curl command line utility.
 - the [git](https://git-scm.com/) command line utility
 
-Note that because of the use of `curl` and `get`, building behind a proxy may be challenging.
+Note that because of the use of `curl` and `get`, building behind a
+proxy may be challenging.
 
 If you are developping for lektor, you will need:
 
-- the [astyle](http://astyle.sourceforge.net/) command line utility, for a beautifull and uniform
-  coding style for C code.
-- the [clang-format](https://releases.llvm.org/download.html) command line utility, for a
-  beautifull and uniform C++ code style. [Here](https://clang.llvm.org/docs/ClangFormatStyleOptions.html)
-  is the list of all the options to put in the `.clang-format` file.
+- the [astyle](http://astyle.sourceforge.net/) command line utility, for
+  a beautifull and uniform coding style for C code.
+- the [clang-format](https://releases.llvm.org/download.html) command
+  line utility, for a beautifull and uniform C++ code style.
+  [Here](https://clang.llvm.org/docs/ClangFormatStyleOptions.html) is
+  the list of all the options to put in the `.clang-format` file.
 
-> If you are having problems build lektor (AC macros not defined), try copy the
-> `.m4` files from `/usr/share/aclocal` to `config/m4`.
+> If you are having problems build lektor (AC macros not defined), try
+copy the `.m4` files from `/usr/share/aclocal` to `config/m4`.
 
 ### Building instructions
 
@@ -98,72 +103,95 @@ The recommended `configure` command is the following:
              CC=clang CXX=clang++         # I prefer clang over gcc
 ```
 
-The sqlite database and the config file will be created automatically if needed, i.e. on the first
-run. If you are upgrading lektor, the config might not be correct. You can delete the config file
-or use the `lkt admin config` to generate the config file again.
-
-> **Important note**: Upgrading the config or the database scheme automatically is not supported
-yet. If you are experiencing weird things with lektord, please try first to delete the database
-and config and regenerate them. There are currently no way of doing a backup of playlists and
-stickers with lektor, this is WIP.
-
-If you are using special modules or are compiling lektor without static modules, you may set their
-**absolute path** inside the lektor's config file.
-
-To generate AppImages, add `--enable-appimage` to the `configure` line. Note
-that the only supported distribution methode is AppImage.
-
-> **Important note**: if you are building using WSL, `lektord` will likely not launch, because
-`XDG_RUNTIME_DIR` is not defined here. This folder is important, this is where most of your
-deamons are puttings theirs sockets and so. Blame Microsoft for that. A workaround is to export
-one: `export XDG_RUNTIME_DIR=$(mktemp -d)` before launching lektord. Be aware that you will have
-issues with sound and videos becouse you will need to set up a X server...
-
-> Currently, supported compilers are: `icc` 19.1.2.254 and above, `gcc` 8.3.0 and above,
-`clang` 7.0.1 and above. It compiles on debian, thus it must compiles on your system (apport from
-CentOS, because I never tested on it, and it no longer exists...).
+The sqlite database and the config file will be created automatically if
+needed, i.e. on the first run. If you are upgrading lektor, the config
+might not be correct. You can delete the config file or use the `lkt
+admin config` to generate the config file again.
+
+> **Important note**: Upgrading the config or the database scheme
+> automatically is not supported
+yet. If you are experiencing weird things with lektord, please try first
+to delete the database and config and regenerate them. There are
+currently no way of doing a backup of playlists and stickers with
+lektor, this is WIP.
+
+If you are using special modules or are compiling lektor without static
+modules, you may set their **absolute path** inside the lektor's config
+file.
+
+To generate AppImages, add `--enable-appimage` to the `configure` line.
+Note that the only supported distribution methode is AppImage.
+
+> **Important note**: if you are building using WSL, `lektord` will
+likely not launch, because `XDG_RUNTIME_DIR` is not defined here. This
+folder is important, this is where most of your deamons are puttings
+theirs sockets and so. Blame Microsoft for that. A workaround is to
+export one: `export XDG_RUNTIME_DIR=$(mktemp -d)` before launching
+lektord. Be aware that you will have issues with sound and videos
+becouse you will need to set up a X server...
+
+> Currently, supported compilers are: `icc` 19.1.2.254 and above, `gcc`
+8.3.0 and above, `clang` 7.0.1 and above. It compiles on debian, thus it
+must compiles on your system (apport from CentOS, because I never tested
+on it, and it no longer exists...).
 
 ## Preparing a kara for lektor
 
-The ideal way of populating lektor is using *Kurisu*. The `update` and `rescan` commands are here
-for that. To import the favorites and playlists from *Kurisu*, use the `import` command.
+The ideal way of populating lektor is using *Kurisu*. The `update` and
+`rescan` commands are here for that. To import the favorites and
+playlists from *Kurisu*, use the `import` command.
 
 ## How to use lektor
 
 ### Launch instructions
 
-To run lektor, you can simply run the binary like: `./lektord`. If lektord did not exited normally
-(i.e. without the `lkt adm kill` command), the database will still store the fact that lektord is
-running. To by-pass it, you will need to launch lektord with the `-F` (forced) option, like `lektord -F`.
+To run lektor, you can simply run the binary like: `./lektord`. If
+lektord did not exited normally (i.e. without the `lkt adm kill`
+command), the database will still store the fact that lektord is
+running. To by-pass it, you will need to launch lektord with the `-F`
+(forced) option, like `lektord -F`.
+
+It is not recommended to launch always lektord with the `-F` option,
+because that way you could launch multiple instances of the lektod
+daemon, which could results in undefined behaviours.
+
+Lektor will use specialized software (hwdec set to yes), if you have an
+nvidia card with optimus (in almose every laptop), please use `optirun`
+or `primusrun`: `optirun ./lektord`
 
-It is not recommended to launch always lektord with the `-F` option, because that way you could launch
-multiple instances of the lektod daemon, which could results in undefined behaviours.
+### How to update the lektord database
 
-Lektor will use specialized software (hwdec set to yes), if you have an nvidia card with optimus (in
-almose every laptop), please use `optirun` or `primusrun`: `optirun ./lektord`
+To update the lektor database, you first need to launch `lektord`, then
+use the `lkt adm update` to update the database and `lkt adm import` to
+import users' favorite lists as playlists.
 
 ### How to send commands to lektor
 
-Lektor is compatible with mpd, which means that you can use any client (only mpc is tested) to interact
-with lektor. Some functions are not *really* compatible (somme work to be done) because mpc *really*
-makes some assumptions. The ideal way is to use `lkt`.
+Lektor is compatible with mpd, which means that you can use any client
+(only mpc is tested) to interact with lektor. Some functions are not
+*really* compatible (somme work to be done) because mpc *really* makes
+some assumptions. The ideal way is to use `lkt`.
 
 ### How to configure lektor
 
-Lektor configuration is done with an INI file. Modules' configuration is also done by the same INI
-file using diferent sections. Lektor searches for the configuration file in that order:
+Lektor configuration is done with an INI file. Modules' configuration is
+also done by the same INI file using diferent sections. Lektor searches
+for the configuration file in that order:
 
 1. `$PWD/lektor.ini`
-2. if `XDG_CONFIG_HOME` defined? `$XDG_CONFIG_HOME/lektor/lektor.ini` : `$HOME/.config/lektor/lektor.ini`
+2. if `XDG_CONFIG_HOME` defined? `$XDG_CONFIG_HOME/lektor/lektor.ini` :
+   `$HOME/.config/lektor/lektor.ini`
 3. `/opt/lektor/lektor.ini`
 4. `/usr/local/etc/lektor.ini`
 5. `/etc/lektor.ini`
 
-To get the default config file, you can use the `lkt adm conf` command. If no config file is found,
-lektord will try to create the `$HOME/.config/lektor/lektor.ini` config file with the default content.
+To get the default config file, you can use the `lkt adm conf` command.
+If no config file is found, lektord will try to create the
+`$HOME/.config/lektor/lektor.ini` config file with the default content.
 
-Be aware that if the home directory or the `XDG_CONFIG_HOME` are too long they will be ignored and
-truncated. You may then get uncomprehensible errors.
+Be aware that if the home directory or the `XDG_CONFIG_HOME` are too
+long they will be ignored and truncated. You may then get
+uncomprehensible errors.
 
 ## Contributing
 
@@ -171,7 +199,8 @@ Please, refer to the [CONTRIBUTING](CONTRIBUTING.md) file.
 
 ## MPD
 
-Lektor is almost MPD compatible, at least it uses the same protocol, which can be gotten
-[here](https://www.musicpd.org/doc/html/protocol.html#). The full support for MPD clients (like mpc
-and ncmpc) is still WIP. For the MPD compatibility list, see the
-[CONTRIBUTING](CONTRIBUTING.md) file.
+Lektor is almost MPD compatible, at least it uses the same protocol,
+which can be gotten
+[here](https://www.musicpd.org/doc/html/protocol.html#). The full
+support for MPD clients (like mpc and ncmpc) is still WIP. For the MPD
+compatibility list, see the [CONTRIBUTING](CONTRIBUTING.md) file.

src/main/lkt.c

@@ -285,7 +285,7 @@ create_socket(const char *host, const char *port)
 
     /* Common part */
     cx = socket(domain, SOCK_STREAM, 0);
-    FAIL_IF(cx <= 0 || connect(cx, ptr_sock, sock_len), "Connect to socket failed");
+    FAIL_IF(cx <= 0 || connect(cx, ptr_sock, sock_len), "Connect to socket failed, is lektord launched?");
     socket_desc = fdopen(cx, "r+");
     FAIL_IF(!socket_desc, "Failed to connect to lektord");
     return socket_desc;