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rwlock of pthread demo

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Hizenberg
2024-04-13 13:24:19 +05:30
parent 54c7d3602b
commit 861976fc69
4 changed files with 227 additions and 0 deletions
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2
.gitignore vendored
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*vsidx *vsidx
*.opendb *.opendb
.vs
out

21
rwlock_example/CMakeLists.txt Normal file
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# CMakeList.txt : CMake project for rwlock_example, include source and define
# project specific logic here.
#
cmake_minimum_required (VERSION 3.8)
# Enable Hot Reload for MSVC compilers if supported.
if (POLICY CMP0141)
cmake_policy(SET CMP0141 NEW)
set(CMAKE_MSVC_DEBUG_INFORMATION_FORMAT "$<IF:$<AND:$<C_COMPILER_ID:MSVC>,$<CXX_COMPILER_ID:MSVC>>,$<$<CONFIG:Debug,RelWithDebInfo>:EditAndContinue>,$<$<CONFIG:Debug,RelWithDebInfo>:ProgramDatabase>>")
endif()
project ("rwlock_example")
# Add source to this project's executable.
add_executable (rwlock_example "rwlock_example.c" )
if (CMAKE_VERSION VERSION_GREATER 3.12)
set_property(TARGET rwlock_example PROPERTY CXX_STANDARD 20)
endif()
# TODO: Add tests and install targets if needed.

101
rwlock_example/CMakePresets.json Normal file
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{
"version": 3,
"configurePresets": [
{
"name": "windows-base",
"hidden": true,
"generator": "Ninja",
"binaryDir": "${sourceDir}/out/build/${presetName}",
"installDir": "${sourceDir}/out/install/${presetName}",
"cacheVariables": {
"CMAKE_C_COMPILER": "cl.exe",
"CMAKE_CXX_COMPILER": "cl.exe"
},
"condition": {
"type": "equals",
"lhs": "${hostSystemName}",
"rhs": "Windows"
}
},
{
"name": "x64-debug",
"displayName": "x64 Debug",
"inherits": "windows-base",
"architecture": {
"value": "x64",
"strategy": "external"
},
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Debug"
}
},
{
"name": "x64-release",
"displayName": "x64 Release",
"inherits": "x64-debug",
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Release"
}
},
{
"name": "x86-debug",
"displayName": "x86 Debug",
"inherits": "windows-base",
"architecture": {
"value": "x86",
"strategy": "external"
},
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Debug"
}
},
{
"name": "x86-release",
"displayName": "x86 Release",
"inherits": "x86-debug",
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Release"
}
},
{
"name": "linux-debug",
"displayName": "Linux Debug",
"generator": "Ninja",
"binaryDir": "${sourceDir}/out/build/${presetName}",
"installDir": "${sourceDir}/out/install/${presetName}",
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Debug"
},
"condition": {
"type": "equals",
"lhs": "${hostSystemName}",
"rhs": "Linux"
},
"vendor": {
"microsoft.com/VisualStudioRemoteSettings/CMake/1.0": {
"sourceDir": "$env{HOME}/.vs/$ms{projectDirName}"
}
}
},
{
"name": "macos-debug",
"displayName": "macOS Debug",
"generator": "Ninja",
"binaryDir": "${sourceDir}/out/build/${presetName}",
"installDir": "${sourceDir}/out/install/${presetName}",
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Debug"
},
"condition": {
"type": "equals",
"lhs": "${hostSystemName}",
"rhs": "Darwin"
},
"vendor": {
"microsoft.com/VisualStudioRemoteSettings/CMake/1.0": {
"sourceDir": "$env{HOME}/.vs/$ms{projectDirName}"
}
}
}
]
}

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rwlock_example/rwlock_example.c Normal file
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#include <stdio.h>
#include <unistd.h>
#include <assert.h>
#include <pthread.h>
static pthread_rwlock_t rw_lock;
static int n_r = 0;
static int n_w = 0;
pthread_mutex_t state_check_mutex;
static void
cs_static_check() {
pthread_mutex_lock(&state_check_mutex);
assert(n_r >= 0 && n_w >= 0); /* cannot be negative */
if (n_r == 0 && n_w == 0) {
//valid condition
}
else if (n_r > 0 && n_w == 0) {
//valid condition
}
else if (n_r == 0 && n_w == 1) {
//valid condition
}
else
assert(0);
printf("n_r = %d, n_w = %d\n", n_r, n_w);
pthread_mutex_unlock(&state_check_mutex);
}
static void
execute_cs() {
cs_status_check();
}
static void
reader_enter_cs() {
pthread_mutex_lock(&state_check_mutex);
n_r++;
pthread_mutex_unlock(&state_check_mutex);
}
static void
reader_leaves_cs() {
pthread_mutex_lock(&state_check_mutex);
n_r--;
pthread_mutex_unlock(&state_check_mutex);
}
static void
writer_enter_cs() {
n_w++;
}
static void
writer_leaves_cs() {
n_w--;
}
void*
read_thread_fn(void* arg) {
while (1) {
pthread_rwlock_rdlock(&rw_lock);
reader_enter_cs();
execute_cs();
reader_leaves_cs();
pthread_rwlock_unlock(&rw_lock);
}
}
void*
write_thread_fn(void* arg) {
while (1) {
pthread_rwlock_wrlock(&rw_lock);
writer_enter_cs();
execute_cs();
writer_leaves_cs();
pthread_rwlock_unlock(&rw_lock);
}
}
int
main(int argc, char* argv[]) {
static pthread_t th1, th2, th3, th4, th5, th6;
pthread_rwlock_init(&rw_lock, NULL);
pthread_mutex_init(&state_check_mutex, NULL);
pthread_create(&th1, NULL, read_thread_fn, NULL);
pthread_create(&th2, NULL, read_thread_fn, NULL);
pthread_create(&th3, NULL, read_thread_fn, NULL);
pthread_create(&th4, NULL, write_thread_fn, NULL);
pthread_create(&th5, NULL, write_thread_fn, NULL);
pthread_create(&th6, NULL, write_thread_fn, NULL);
pthread_exit(0);
return 0;
}