some thread API examples

threads-api/Makefile

@@ -0,0 +1,21 @@
+CC     := gcc
+CFLAGS := -Wall -Werror -I../include 
+
+SRCS   := thread_create.c \
+	thread_create_simple_args.c \
+	thread_create_with_return_args.c
+
+OBJS   := ${SRCS:c=o}
+PROGS  := ${SRCS:.c=}
+
+.PHONY: all
+all: ${PROGS}
+
+${PROGS} : % : %.o Makefile
+	${CC} $< -o $@ -pthread
+
+clean:
+	rm -f ${PROGS} ${OBJS}
+
+%.o: %.c Makefile
+	${CC} ${CFLAGS} -c $<

threads-api/README.md

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+
+# Threads API
+
+Some simple examples of how to use POSIX thread APIs.
+
+Relevant files:
+- `thread_create.c`: A simple thread creation program, with args passed to the
+thread. 
+- `thread_create_with_return_args.c`: Return values from the thread to the
+parent.
+- `thread_create_simple_args.c`: Simpler argument/return value passing for the
+lazy. 
+
+Type `make` to build; each file `foo.c` generates an executable `foo` which
+you can then run, e.g.:
+
+```sh
+prompt> ./thread_create
+```
+

threads-api/thread_create.c

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+#include <assert.h>
+#include <stdio.h>
+#include <pthread.h>
+
+typedef struct {
+    int a;
+    int b;
+} myarg_t;
+
+void *mythread(void *arg) {
+    myarg_t *args = (myarg_t *) arg;
+    printf("%d %d\n", args->a, args->b);
+    return NULL;
+}
+
+int main(int argc, char *argv[]) {
+    pthread_t p;
+    myarg_t args = { 10, 20 };
+
+    int rc = pthread_create(&p, NULL, mythread, &args);
+    assert(rc == 0);
+    (void) pthread_join(p, NULL);
+    printf("done\n");
+    return 0;
+}

threads-api/thread_create_simple_args.c

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+#include <stdio.h>
+#include <pthread.h>
+#include "common_threads.h"
+
+void *mythread(void *arg) {
+    long long int value = (long long int) arg;
+    printf("%lld\n", value);
+    return (void *) (value + 1);
+}
+
+int main(int argc, char *argv[]) {
+    pthread_t p;
+    long long int rvalue;
+    Pthread_create(&p, NULL, mythread, (void *) 100);
+    Pthread_join(p, (void **) &rvalue);
+    printf("returned %lld\n", rvalue);
+    return 0;
+}
+

threads-api/thread_create_with_return_args.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include "common_threads.h"
+
+typedef struct {
+    int a;
+    int b;
+} myarg_t;
+
+typedef struct {
+    int x;
+    int y;
+} myret_t;
+
+void *mythread(void *arg) {
+    myarg_t *args = (myarg_t *) arg;
+    printf("args %d %d\n", args->a, args->b);
+    myret_t *rvals = malloc(sizeof(myret_t));
+    assert(rvals != NULL);
+    rvals->x = 1;
+    rvals->y = 2;
+    return (void *) rvals;
+}
+
+int main(int argc, char *argv[]) {
+    pthread_t p;
+    myret_t *rvals;
+    myarg_t args = { 10, 20 };
+    Pthread_create(&p, NULL, mythread, &args);
+    Pthread_join(p, (void **) &rvals);
+    printf("returned %d %d\n", rvals->x, rvals->y);
+    free(rvals);
+    return 0;
+}
+