From 7cd6a5437c263a4e2b64bafdf780d60ce51f941f Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Thu, 1 Sep 2022 23:14:03 -0400
Subject: Simplify thread and semaphore status codes

---
 include/zix/common.h | 1 +
 include/zix/sem.h    | 5 +++--
 include/zix/thread.h | 4 ++--
 src/sem.c            | 7 +++----
 src/status.c         | 6 ++++++
 test/test_sem.c      | 4 ++--
 test/test_status.c   | 2 +-
 7 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/include/zix/common.h b/include/zix/common.h
index 0cefd55..a097edd 100644
--- a/include/zix/common.h
+++ b/include/zix/common.h
@@ -29,6 +29,7 @@ typedef enum {
   ZIX_STATUS_TIMEOUT,
   ZIX_STATUS_OVERFLOW,
   ZIX_STATUS_NOT_SUPPORTED,
+  ZIX_STATUS_UNAVAILABLE,
 } ZixStatus;
 
 /// Return a string describing a status code
diff --git a/include/zix/sem.h b/include/zix/sem.h
index 4c82f17..41b9860 100644
--- a/include/zix/sem.h
+++ b/include/zix/sem.h
@@ -97,8 +97,9 @@ zix_sem_wait(ZixSem* ZIX_NONNULL sem);
 /**
    Non-blocking version of wait().
 
-   @return #ZIX_STATUS_SUCCESS if `sem` was decremented, #ZIX_STATUS_TIMEOUT if
-   it was already zero, or #ZIX_STATUS_BAD_ARG if `sem` is invalid.
+   @return #ZIX_STATUS_SUCCESS if `sem` was decremented,
+   #ZIX_STATUS_UNAVAILABLE if it was already zero, or #ZIX_STATUS_BAD_ARG if
+   `sem` is invalid.
 */
 ZIX_API
 ZixStatus
diff --git a/include/zix/thread.h b/include/zix/thread.h
index bad939f..482315a 100644
--- a/include/zix/thread.h
+++ b/include/zix/thread.h
@@ -103,9 +103,9 @@ zix_thread_create(ZixThread*    thread,
   pthread_attr_setstacksize(&attr, stack_size);
 
   const int ret = pthread_create(thread, NULL, function, arg);
-  pthread_attr_destroy(&attr);
 
-  return ret == EAGAIN ? ZIX_STATUS_NO_MEM : zix_errno_status(ret);
+  pthread_attr_destroy(&attr);
+  return zix_errno_status(ret);
 }
 
 static inline ZixStatus
diff --git a/src/sem.c b/src/sem.c
index a577b08..325eaa4 100644
--- a/src/sem.c
+++ b/src/sem.c
@@ -61,7 +61,7 @@ zix_sem_try_wait(ZixSem* sem)
   const kern_return_t   r    = semaphore_timedwait(sem->sem, zero);
 
   return (r == KERN_SUCCESS)               ? ZIX_STATUS_SUCCESS
-         : (r == KERN_OPERATION_TIMED_OUT) ? ZIX_STATUS_TIMEOUT
+         : (r == KERN_OPERATION_TIMED_OUT) ? ZIX_STATUS_UNAVAILABLE
                                            : ZIX_STATUS_ERROR;
 }
 
@@ -114,7 +114,7 @@ zix_sem_try_wait(ZixSem* sem)
   const DWORD r = WaitForSingleObject(sem->sem, 0);
 
   return (r == WAIT_OBJECT_0)  ? ZIX_STATUS_SUCCESS
-         : (r == WAIT_TIMEOUT) ? ZIX_STATUS_TIMEOUT
+         : (r == WAIT_TIMEOUT) ? ZIX_STATUS_UNAVAILABLE
                                : ZIX_STATUS_ERROR;
 }
 
@@ -171,8 +171,7 @@ zix_sem_try_wait(ZixSem* sem)
     // Interrupted, try again
   }
 
-  return r ? (errno == EAGAIN ? ZIX_STATUS_TIMEOUT : zix_errno_status(errno))
-           : ZIX_STATUS_SUCCESS;
+  return r ? zix_errno_status(errno) : ZIX_STATUS_SUCCESS;
 }
 
 ZixStatus
diff --git a/src/status.c b/src/status.c
index ed48952..380d370 100644
--- a/src/status.c
+++ b/src/status.c
@@ -31,6 +31,8 @@ zix_strerror(const ZixStatus status)
     return "Overflow";
   case ZIX_STATUS_NOT_SUPPORTED:
     return "Not supported";
+  case ZIX_STATUS_UNAVAILABLE:
+    return "Resource unavailable";
   }
   return "Unknown error";
 }
@@ -41,6 +43,10 @@ zix_errno_status(const int e)
   switch (e) {
   case 0:
     return ZIX_STATUS_SUCCESS;
+#ifdef EAGAIN
+  case EAGAIN:
+    return ZIX_STATUS_UNAVAILABLE;
+#endif
 #ifdef EEXIST
   case EEXIST:
     return ZIX_STATUS_EXISTS;
diff --git a/test/test_sem.c b/test/test_sem.c
index f2b2794..36d01c5 100644
--- a/test/test_sem.c
+++ b/test/test_sem.c
@@ -45,10 +45,10 @@ static void
 test_try_wait(void)
 {
   assert(!zix_sem_init(&sem, 0));
-  assert(zix_sem_try_wait(&sem) == ZIX_STATUS_TIMEOUT);
+  assert(zix_sem_try_wait(&sem) == ZIX_STATUS_UNAVAILABLE);
   assert(!zix_sem_post(&sem));
   assert(!zix_sem_try_wait(&sem));
-  assert(zix_sem_try_wait(&sem) == ZIX_STATUS_TIMEOUT);
+  assert(zix_sem_try_wait(&sem) == ZIX_STATUS_UNAVAILABLE);
   assert(!zix_sem_destroy(&sem));
 }
 
diff --git a/test/test_status.c b/test/test_status.c
index 298b520..1a76ac2 100644
--- a/test/test_status.c
+++ b/test/test_status.c
@@ -37,7 +37,7 @@ test_strerror(void)
   const char* msg = zix_strerror(ZIX_STATUS_SUCCESS);
   assert(!strcmp(msg, "Success"));
 
-  for (int i = ZIX_STATUS_ERROR; i <= ZIX_STATUS_NOT_SUPPORTED; ++i) {
+  for (int i = ZIX_STATUS_ERROR; i <= ZIX_STATUS_UNAVAILABLE; ++i) {
     msg = zix_strerror((ZixStatus)i);
     assert(strcmp(msg, "Success"));
   }
-- 
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