Create example01

This commit is contained in:
Stephen Seo 2021-08-20 17:35:11 +09:00
parent aa6a25199d
commit ca8ca5928c
4 changed files with 87 additions and 0 deletions

4
README.md Normal file
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# What this repo is
This repo has some examples using multi-threaded-programming because someone
asked about how it works.

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build*/
compile_commands.json
.cache/

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cmake_minimum_required(VERSION 3.9)
project(Example01_SingleThread_C_IMPL)
set(Example01_SOURCES
"${CMAKE_CURRENT_SOURCE_DIR}/src/main.c")
set(CMAKE_C_FLAGS "-Wall -Wextra -Wpedantic")
set(CMAKE_C_FLAGS_DEBUG "-O0 -g")
set(CMAKE_C_FLAGS_RELEASE "-O3 -DNDEBUG")
if(NOT CMAKE_BUILD_TYPE OR "${CMAKE_BUILD_TYPE}" MATCHES ^$)
set(CMAKE_BUILD_TYPE "Debug")
message("CMAKE_BUILD_TYPE is set to Debug by default")
endif()
add_executable(Example01
${Example01_SOURCES})
target_link_libraries(Example01 PUBLIC pthread)

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#include <stdio.h>
#include <threads.h>
#include <string.h>
typedef struct ThreadData {
mtx_t mutex;
int lock_before_printing;
} ThreadData;
int functionCalledByThread(void *user_data) {
ThreadData *data = (ThreadData*)user_data;
if(data->lock_before_printing != 0) {
// lock before printing
mtx_lock(&data->mutex);
}
puts("Hello from spawned thread");
if(data->lock_before_printing != 0) {
// unlock after printing
mtx_unlock(&data->mutex);
}
return 0;
}
int main(int argc, char **argv) {
// create the ThreadData that is shared with the thread
ThreadData td;
mtx_init(&td.mutex, mtx_plain);
td.lock_before_printing = 1;
// check args
--argc; ++argv;
while(argc > 0) {
if(strcmp("-n", argv[0]) == 0 || strcmp("--no-lock", argv[0]) == 0) {
td.lock_before_printing = 0;
puts("Disabling use of mutex before printing");
}
--argc; ++argv;
}
// create the thread
thrd_t thread_handle;
thrd_create(&thread_handle, functionCalledByThread, &td);
if(td.lock_before_printing != 0) {
// lock before printing
mtx_lock(&td.mutex);
}
puts("Hello from main thread");
if(td.lock_before_printing != 0) {
// unlock after printing
mtx_unlock(&td.mutex);
}
thrd_join(thread_handle, NULL);
// cleanup
mtx_destroy(&td.mutex);
return 0;
}