ST: Research adds examples that demos pthread and helloworld. v6.0.118 (#3989)

1. `trunk/research/st/exceptions.cpp` About exceptions with ST, works
well on linux and mac, not work on cygwin.
2. `trunk/research/st/pthreads.cpp` About pthreads with ST, works well
on all platforms.
3. `trunk/research/st/hello.cpp` Hello world, without ST, works well on
all platforms.
4. `trunk/research/st/hello-world.cpp` Hello world, with ST, works well
on all platforms.
5. `trunk/research/st/hello-st.cpp` A very simple version for hello
world with ST, works well on all platforms.

trunk/research/st/exceptions.cpp

@@ -0,0 +1,29 @@
+/*
+# !!! ST does not support C++ exceptions on cygwin !!!
+g++ exceptions.cpp ../../objs/st/libst.a -g -O0 -o exceptions && ./exceptions
+*/
+#include <stdio.h>
+#include <exception>
+#include "../../objs/st/st.h"
+
+int handle_exception() {
+    try {
+        throw 3;
+    } catch (...) {
+        return 5;
+    }
+}
+
+void* foo(void* arg) {
+    int r0 = handle_exception();
+    printf("r0=%d\n", r0);
+    return NULL;
+}
+
+int main(int argc, char** argv) {
+    st_init();
+    st_thread_create(foo, NULL, 0, 0);
+    st_thread_exit(NULL);
+    return 0;
+}
+

trunk/research/st/hello-st.cpp

@@ -0,0 +1,16 @@
+/*
+g++ hello-st.cpp ../../objs/st/libst.a -g -O0 -o hello-st && ./hello-st
+*/
+#include <stdio.h>
+#include "../../objs/st/st.h"
+
+void foo() {
+    st_init();
+    st_sleep(1);
+    printf("Hello World, ST!\n");
+}
+
+int main() {
+    foo();
+    return 0;
+}

trunk/research/st/hello-world.cpp

@@ -0,0 +1,19 @@
+/*
+g++ hello-world.cpp ../../objs/st/libst.a -g -O0 -o hello-world && ./hello-world
+*/
+#include <stdio.h>
+#include "../../objs/st/st.h"
+
+void foo() {
+    st_init();
+
+    for (int i = 0; ; i++) {
+        st_sleep(1);
+        printf("#%d: main: working\n", i);
+    }
+}
+
+int main() {
+    foo();
+    return 0;
+}

trunk/research/st/hello.cpp

@@ -0,0 +1,11 @@
+/*
+ g++ hello.cpp -g -O0 -o hello && ./hello
+ */
+
+void foo() {
+}
+
+int main(int argc, char** argv) {
+    foo();
+    return 0;
+}

trunk/research/st/pthreads.cpp

@@ -0,0 +1,36 @@
+/*
+Directly compile c++ source and execute:
+    g++ pthreads.cpp ../../objs/st/libst.a -g -O0 -o pthreads && ./pthreads
+*/
+#include <stdio.h>
+#include <pthread.h>
+#include "../../objs/st/st.h"
+
+void* foo(void* arg) {
+    while (true) {
+        printf("Hello, child thread\n");
+        st_sleep(1);
+    }
+    return NULL;
+}
+
+void* pfn(void* arg) {
+    st_init();
+    st_thread_create(foo, NULL, 0, 0);
+    st_thread_exit(NULL);
+    return NULL;
+}
+
+int main(int argc, char** argv) {
+    st_init();
+
+    pthread_t trd;
+    pthread_create(&trd, NULL, pfn, NULL);
+
+    while (true) {
+        printf("Hello, main thread\n");
+        st_sleep(1);
+    }
+    return 0;
+}
+