Fix assumptions that pthread functions set errno (valkey-io#2526)

pthread functions return the error instead of setting errno.

Fixes valkey-io#2525

Signed-off-by: Ted Lyngmo <ted@lyncon.se>

Author: TedLyngmo

src/bio.c

@@ -152,8 +152,9 @@ void bioInit(void) {
      * responsible for. */
     for (j = 0; j < BIO_WORKER_NUM; j++) {
         void *arg = (void *)(unsigned long)j;
-        if (pthread_create(&thread, &attr, bioProcessBackgroundJobs, arg) != 0) {
-            serverLog(LL_WARNING, "Fatal: Can't initialize Background Jobs. Error message: %s", strerror(errno));
+        int err = pthread_create(&thread, &attr, bioProcessBackgroundJobs, arg);
+        if (err) {
+            serverLog(LL_WARNING, "Fatal: Can't initialize Background Jobs. Error message: %s", strerror(err));
             exit(1);
         }
         bio_threads[j] = thread;
@@ -239,8 +240,9 @@ void *bioProcessBackgroundJobs(void *arg) {
      * receive the watchdog signal. */
     sigemptyset(&sigset);
     sigaddset(&sigset, SIGALRM);
-    if (pthread_sigmask(SIG_BLOCK, &sigset, NULL))
-        serverLog(LL_WARNING, "Warning: can't mask SIGALRM in bio.c thread: %s", strerror(errno));
+    int err = pthread_sigmask(SIG_BLOCK, &sigset, NULL);
+    if (err)
+        serverLog(LL_WARNING, "Warning: can't mask SIGALRM in bio.c thread: %s", strerror(err));
 
     bio_thread_id = worker;
 

src/io_threads.c

@@ -269,8 +269,9 @@ static void createIOThread(int id) {
     pthread_mutex_init(&io_threads_mutex[id], NULL);
     IOJobQueue_init(&io_jobs[id], IO_JOB_QUEUE_SIZE);
     pthread_mutex_lock(&io_threads_mutex[id]); /* Thread will be stopped. */
-    if (pthread_create(&tid, NULL, IOThreadMain, (void *)(long)id) != 0) {
-        serverLog(LL_WARNING, "Fatal: Can't initialize IO thread, pthread_create failed with: %s", strerror(errno));
+    int err = pthread_create(&tid, NULL, IOThreadMain, (void *)(long)id);
+    if (err) {
+        serverLog(LL_WARNING, "Fatal: Can't initialize IO thread, pthread_create failed with: %s", strerror(err));
         exit(1);
     }
     io_threads[id] = tid;