internal: silence compiler warnings about unused return values (#13997)

* misc: silence warnings about ignoring return value on reads

silence warnings on ignored return values on read() and print an error
if it occurs.

* misc: silence warnings about ignoring return value on writes

silence warnings on ignored return values on write() and print an error
where we can, or pass them the maybe_unused attribute.

* misc: silence warnings about ignoring return value on pipe

silence warnings on ignored return value on pipe(), print an error and
exit on failure.

src/Compositor.cpp

@@ -117,8 +117,8 @@ static void handleUnrecoverableSignal(int sig) {
 
     // Kill the program if the crash-reporter is caught in a deadlock.
     signal(SIGALRM, [](int _) {
-        char const* msg = "\nCrashReporter exceeded timeout, forcefully exiting\n";
-        write(2, msg, strlen(msg));
+        char const*           msg = "\nCrashReporter exceeded timeout, forcefully exiting\n";
+        [[maybe_unused]] auto w   = write(2, msg, strlen(msg));
         abort();
     });
     alarm(15);
@@ -550,8 +550,8 @@ void CCompositor::cleanup() {
     if (!m_wlDisplay)
         return;
 
-    if (m_watchdogWriteFd.isValid())
-        write(m_watchdogWriteFd.get(), "end", 3);
+    if (m_watchdogWriteFd.isValid()) [[maybe_unused]]
+        auto w = write(m_watchdogWriteFd.get(), "end", 3);
 
     signal(SIGABRT, SIG_DFL);
     signal(SIGSEGV, SIG_DFL);
@@ -803,8 +803,10 @@ void CCompositor::startCompositor() {
 
     Event::bus()->m_events.ready.emit();
 
-    if (m_watchdogWriteFd.isValid())
-        write(m_watchdogWriteFd.get(), "vax", 3);
+    if (m_watchdogWriteFd.isValid()) {
+        if (write(m_watchdogWriteFd.get(), "vax", 3) < 0)
+            Log::logger->log(Log::ERR, "startCompositor: failed to write to watchdogWriteFd {}: {}", m_watchdogWriteFd.get(), strerror(errno));
+    }
 
     // This blocks until we are done.
     Log::logger->log(Log::DEBUG, "Hyprland is ready, running the event loop!");

src/debug/crash/CrashReporter.cpp

@@ -43,7 +43,7 @@ static char const* getRandomMessage() {
 }
 
 [[noreturn]] static inline void exitWithError(char const* err) {
-    write(STDERR_FILENO, err, strlen(err));
+    [[maybe_unused]] auto w = write(STDERR_FILENO, err, strlen(err));
     // perror() is not signal-safe, but we use it here
     // because if the crash-handler already crashed, it can't get any worse.
     perror("");

src/helpers/MainLoopExecutor.cpp

@@ -1,6 +1,7 @@
 #include "MainLoopExecutor.hpp"
 #include "../managers/eventLoop/EventLoopManager.hpp"
 #include "../macros.hpp"
+#include <cstring>
 #include <unistd.h>
 
 static int onDataRead(int fd, uint32_t mask, void* data) {
@@ -26,7 +27,8 @@ CMainLoopExecutor::~CMainLoopExecutor() {
 
 void CMainLoopExecutor::signal() {
     const char* amogus = "h";
-    write(m_writeFd.get(), amogus, 1);
+    if (write(m_writeFd.get(), amogus, 1) < 0)
+        Log::logger->log(Log::ERR, "signal: failed to write to fd {}: {}", m_writeFd.get(), strerror(errno));
 }
 
 void CMainLoopExecutor::onFired() {

src/managers/eventLoop/EventLoopManager.cpp

@@ -4,6 +4,7 @@
 #include "../../config/shared/inotify/ConfigWatcher.hpp"
 
 #include <algorithm>
+#include <cstring>
 #include <limits>
 #include <ranges>
 
@@ -41,7 +42,8 @@ static int timerWrite(int fd, uint32_t mask, void* data) {
         Log::logger->log(Log::ERR, "timerWrite: triggered a non readable event on fd : {}", fd);
     else {
         uint64_t expirations;
-        read(fd, &expirations, sizeof(expirations));
+        if (read(fd, &expirations, sizeof(expirations)) < 0)
+            Log::logger->log(Log::ERR, "timerWrite: read failed on fd {}: {}", fd, strerror(errno));
     }
 
     g_pEventLoopManager->onTimerFire();

src/xwayland/Server.cpp

@@ -222,7 +222,10 @@ bool CXWaylandServer::tryOpenSockets() {
             continue;
 
         char pidstr[12] = {0};
-        read(fd.get(), pidstr, sizeof(pidstr) - 1);
+        if (read(fd.get(), pidstr, sizeof(pidstr) - 1) < 0) {
+            Log::logger->log(Log::ERR, "Failed to read on fd {}: {}", fd.get(), strerror(errno));
+            continue;
+        }
 
         int32_t pid = 0;
         try {

start/src/core/Instance.cpp

@@ -81,7 +81,8 @@ void CHyprlandInstance::runHyprlandThread(bool safeMode) {
                 break;
         }
 
-        write(m_wakeupWrite.get(), "vax", 3);
+        if (write(m_wakeupWrite.get(), "vax", 3) < 0)
+            g_logger->log(Hyprutils::CLI::LOG_ERR, "Failed to write to wakeup fd {}: {}", m_wakeupWrite.get(), strerror(errno));
 
         std::fflush(stdout);
         std::fflush(stderr);
@@ -96,8 +97,14 @@ void CHyprlandInstance::forceQuit() {
 }
 
 void CHyprlandInstance::clearFd(const Hyprutils::OS::CFileDescriptor& fd) {
+    if (!fd.isReadable()) {
+        g_logger->log(Hyprutils::CLI::LOG_ERR, "Can't clear a unreadable fd");
+        return;
+    }
+
     static std::array<char, 1024> buf;
-    read(fd.get(), buf.data(), 1023);
+    if (read(fd.get(), buf.data(), 1023) < 0)
+        g_logger->log(Hyprutils::CLI::LOG_ERR, "Failed clearing fd {}: {}", fd.get(), strerror(errno));
 }
 
 void CHyprlandInstance::dispatchHyprlandEvent() {
@@ -132,12 +139,18 @@ void CHyprlandInstance::dispatchHyprlandEvent() {
 
 bool CHyprlandInstance::run(bool safeMode) {
     int pipefds[2];
-    pipe(pipefds);
+    if (pipe(pipefds) != 0) {
+        g_logger->log(Hyprutils::CLI::LOG_ERR, "pipe() failed, exiting");
+        exit(1);
+    }
 
     m_fromHlPid = CFileDescriptor{pipefds[0]};
     m_toHlPid   = CFileDescriptor{pipefds[1]};
 
-    pipe(pipefds);
+    if (pipe(pipefds) != 0) {
+        g_logger->log(Hyprutils::CLI::LOG_ERR, "pipe() failed, exiting");
+        exit(1);
+    }
 
     m_wakeupRead  = CFileDescriptor{pipefds[0]};
     m_wakeupWrite = CFileDescriptor{pipefds[1]};