diff --git a/is-thread-safe/main.c b/is-thread-safe/main.c
new file mode 100644
index 0000000..fe50a0c
--- /dev/null
+++ b/is-thread-safe/main.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <libpq-fe.h>
+
+int main(int argc, char **argv) {
+  /*declarations*/
+  int isThreadSafe=0;
+  printf("main() Started...\n");
+  isThreadSafe=PQisthreadsafe();
+  if(isThreadSafe==1){
+    printf("main() libpq is thread-safe\n");
+  }else{
+    printf("main() libpq is NOT thread-safe\n");
+  }
+  printf("main() Done.\n");
+
+  return 0;
+}
diff --git a/is-thread-safe/makefile b/is-thread-safe/makefile
new file mode 100644
index 0000000..b14baca
--- /dev/null
+++ b/is-thread-safe/makefile
@@ -0,0 +1,24 @@
+# Docu
+#
+#$@ is the name of the file to be made
+#$? is the names of the changed dependents
+#$< the name of the related file that caused the action
+#$* the prefix shared by target and dependent files
+#
+# Others
+RM      = /bin/rm -f
+#
+# Source, Executable, Includes, Library Defines
+EXE    = main
+#
+# Compiler, Linker Defines
+CC      = /usr/bin/gcc
+#
+all: main.o
+	$(CC) main.c -I/usr/include/postgresql -L/usr/lib/x86_64-linux-gnu -lpq -std=c99 -Wall -o $(EXE)
+#
+main.o:
+	$(CC) -c main.c -I/usr/include/postgresql
+# Clean Up Objects, Exectuables, Dumps out of source directory
+clean:
+	$(RM) *.o $(EXE) *~
diff --git a/is-thread-safe/readme.md b/is-thread-safe/readme.md
new file mode 100644
index 0000000..a0dc22d
--- /dev/null
+++ b/is-thread-safe/readme.md
@@ -0,0 +1,23 @@
+* build
+
+```
+make
+```
+
+* run
+
+```
+./main 'postgresql://begerad:secret@localhost:5432/sib00_vbn_gtfs'
+```
+
+* or run
+
+```
+./main 'postgresql://begerad:secret@localhost:5432/vbn_data'
+```
+
+* or run
+
+```
+./main "host=localhost port=5432 user=begerad password=<secret> dbname=vbn_data"
+```
\ No newline at end of file