This happened while following the gstreamer plugin example - plugins

Question

First I downloaded git via git clone https://gitlab.freedesktop.org/gstreamer/gst-template.git command
And shell $ cd gst-template/gst-plugin/src
Completed entering the shell $ ../tools/make_element MyFilter command
And I did meson build in /gst-template, then ninja -C build, so the log came out as below.
ninja: Entering directory `build/'
[1/4] Compiling C object gst-plugin/libgstplugin.so.p/src_gstplugin.c.o
FAILED: gst-plugin/libgstplugin.so.p/src_gstplugin.c.o
cc -Igst-plugin/libgstplugin.so.p -Igst-plugin -I../gst-plugin -I/usr/include/gstreamer-1.0 -I/usr/include/glib-2.0 -I/usr/lib/aarch64-linux-gnu/glib-2.0/include - fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -g -fPIC -pthread -DHAVE_CONFIG_H -MD -MQ gst- plugin/libgstplugin.so.p/src_gstplugin.c.o -MF gst-plugin/libgstplugin.so.p/src_gstplugin.c.o.d -o gst-plugin/libgstplugin.so.p/src_gstplugin.c.o -c ../gst- plugin/src/gstplugin.c
../gst-plugin/src/gstplugin.c:102:45: error: expected ‘)’ before string constant
GST_ELEMENT_REGISTER_DEFINE (myfirstplugin, "myfirstplugin", GST_RANK_NONE,
^~~~~~~~~~
../gst-plugin/src/gstplugin.c: In function ‘plugin_init’:
../gst-plugin/src/gstplugin.c:266:10: warning: implicit declaration of function ‘GST_ELEMENT_REGISTER’; did you mean ‘GST_ELEMENT_CAST’? [-Wimplicit- function-declaration]
return GST_ELEMENT_REGISTER (myfirstplugin, plugin);
^~~~~~~~~
GST_ELEMENT_CAST
../gst-plugin/src/gstplugin.c:266:32: error: ‘myfirstplugin’ undeclared (first use in this function); did you mean ‘GstPlugin’?
return GST_ELEMENT_REGISTER (myfirstplugin, plugin);
^~~~~~~~~~~~~
GstPlugin
../gst-plugin/src/gstplugin.c:266:32: note: each undeclared identifier is reported only once for each function it appears in
../gst-plugin/src/gstplugin.c:267:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
[2/4] Compiling C object gst-plugin/libgstaudiofilterexample.so.p/src_gstaudiofilter.c.o
FAILED: gst-plugin/libgstaudiofilterexample.so.p/src_gstaudiofilter.c.o
cc -Igst-plugin/libgstaudiofilterexample.so.p -Igst-plugin -I../gst-plugin -I/usr/include/gstreamer-1.0 -I/usr/include/glib-2.0 -I/usr/lib/aarch64-linux-gnu/glib- 2.0/include -I/usr/include/orc-0.4 -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -g -fPIC -pthread -DHAVE_CONFIG_H -MD -MQ gst-plugin/libgstaudiofilterexample.so.p/src_gstaudiofilter.c.o -MF gst-plugin/libgstaudiofilterexample.so.p/src_gstaudiofilter.c.o.d -o gst- plugin/libgstaudiofilterexample.so.p/src_gstaudiofilter.c.o -c ../gst-plugin/src/gstaudiofilter.c
../gst-plugin/src/gstaudiofilter.c:99:51: error: expected ‘)’ before string constant
GST_ELEMENT_REGISTER_DEFINE (audiofiltertemplate, "audiofiltertemplate",
^~~~~~~~~~~~~~
../gst-plugin/src/gstaudiofilter.c: In function ‘plugin_init’:
../gst-plugin/src/gstaudiofilter.c:311:10: warning: implicit declaration of function ‘GST_ELEMENT_REGISTER’; did you mean ‘GST_ELEMENT_CAST’? [-Wimplicit- function-declaration]
return GST_ELEMENT_REGISTER (audiofiltertemplate, plugin);
^~~~~~~~~
GST_ELEMENT_CAST
../gst-plugin/src/gstaudiofilter.c:311:32: error: ‘audiofiltertemplate’ undeclared (first use in this function); did you mean ‘GstAudioFilterTemplate’?
return GST_ELEMENT_REGISTER (audiofiltertemplate, plugin);
^~~~~~~~~~~~
GstAudioFilterTemplate
../gst-plugin/src/gstaudiofilter.c:311:32: note: each undeclared identifier is reported only once for each function it appears in
../gst-plugin/src/gstaudiofilter.c:312:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
ninja: build stopped: subcommand failed.

Answer 1

The installed gstreamer version doesn't match to the cloned version from the git repository.
Use gst-launch-1.0 --version to determine which version you have installed.
You need at least 1.18 to use the gst-plugin example.