Fix wait loop and void cast (#24)

* Simplify EINTR/ECANCEL error handling

1. Add semaphore uninterruptible wait function
2 .Replace semaphore wait loop with a single uninterruptible wait
3. Replace all sem_xxx to nxsem_xxx

* Unify the void cast usage

1. Remove void cast for function because many place ignore the returned value witout cast
2. Replace void cast for variable with UNUSED macro

binfmt/binfmt_exec.c

@@ -204,7 +204,7 @@ int exec(FAR const char *filename, FAR char * const *argv,
 
 errout_with_lock:
   sched_unlock();
-  (void)unload_module(bin);
+  unload_module(bin);
 errout_with_argv:
   binfmt_freeargv(bin);
 errout_with_bin:

binfmt/binfmt_execmodule.c

@@ -296,7 +296,7 @@ errout_with_tcbinit:
 
 errout_with_addrenv:
 #if defined(CONFIG_ARCH_ADDRENV) && defined(CONFIG_BUILD_KERNEL)
-  (void)up_addrenv_restore(&oldenv);
+  up_addrenv_restore(&oldenv);
 
 errout_with_tcb:
 #endif

binfmt/builtin.c

@@ -188,7 +188,7 @@ int builtin_initialize(void)
 
 void builtin_uninitialize(void)
 {
-  (void)unregister_binfmt(&g_builtin_binfmt);
+  unregister_binfmt(&g_builtin_binfmt);
 }
 
 #endif /* HAVE_BUILTIN_CONTEXT */

binfmt/elf.c

@@ -354,7 +354,7 @@ int elf_initialize(void)
 
 void elf_uninitialize(void)
 {
-  (void)unregister_binfmt(&g_elfbinfmt);
+  unregister_binfmt(&g_elfbinfmt);
 }
 
 #endif /* CONFIG_ELF */

binfmt/libelf/libelf_bind.c

@@ -432,7 +432,7 @@ int elf_bind(FAR struct elf_loadinfo_s *loadinfo,
    */
 
 #if 0 /* REVISIT... has some problems */
-  (void)up_addrenv_coherent(&loadinfo->addrenv);
+  up_addrenv_coherent(&loadinfo->addrenv);
 #else
   up_coherent_dcache(loadinfo->textalloc, loadinfo->textsize);
   up_coherent_dcache(loadinfo->dataalloc, loadinfo->datasize);

binfmt/libelf/libelf_load.c

@@ -368,7 +368,7 @@ int elf_load(FAR struct elf_loadinfo_s *loadinfo)
 
 errout_with_addrenv:
 #ifdef CONFIG_ARCH_ADDRENV
-  (void)elf_addrenv_restore(loadinfo);
+  elf_addrenv_restore(loadinfo);
 #endif
 
 errout_with_buffers:

binfmt/libnxflat/libnxflat_addrenv.c

@@ -169,7 +169,7 @@ int nxflat_addrenv_alloc(FAR struct nxflat_loadinfo_s *loadinfo, size_t envsize)
   return OK;
 
 errout_with_addrenv:
-  (void)up_addrenv_destroy(&loadinfo->addrenv);
+  up_addrenv_destroy(&loadinfo->addrenv);
   loadinfo->addrenv = 0;
 
 errout_with_dspace:

binfmt/libnxflat/libnxflat_bind.c

@@ -475,7 +475,7 @@ static inline int nxflat_bindimports(FAR struct nxflat_loadinfo_s *loadinfo,
             {
               berr("Exported symbol \"%s\" not found\n", symname);
 #ifdef CONFIG_ARCH_ADDRENV
-              (void)nxflat_addrenv_restore(loadinfo);
+              nxflat_addrenv_restore(loadinfo);
 #endif
               return -ENOENT;
             }

binfmt/libnxflat/libnxflat_load.c

@@ -215,9 +215,9 @@ int nxflat_load(struct nxflat_loadinfo_s *loadinfo)
 
 errout:
 #ifdef CONFIG_ARCH_ADDRENV
-  (void)nxflat_addrenv_restore(loadinfo);
+  nxflat_addrenv_restore(loadinfo);
 #endif
-  (void)nxflat_unload(loadinfo);
+  nxflat_unload(loadinfo);
   return ret;
 }
 

binfmt/nxflat.c

@@ -315,7 +315,7 @@ int nxflat_initialize(void)
 
 void nxflat_uninitialize(void)
 {
-  (void)unregister_binfmt(&g_nxflatbinfmt);
+  unregister_binfmt(&g_nxflatbinfmt);
 }
 
 #endif /* CONFIG_NXFLAT */