feat(core) virtual errno/GetLastError() parameters

This change replaces the thread-local storage of errno & GetLastError() in JNIEnv->reserved2 with virtual output parameters passed explicitly by the caller.
LWJGL · Oct 4, 2024 · 2b12f5e · 2b12f5e
1 parent 63c08d5
commit 2b12f5e
Show file tree

Hide file tree

Showing 60 changed files with 1,704 additions and 1,098 deletions.
diff --git a/build.xml b/build.xml
@@ -854,7 +854,7 @@
             <include name="org/lwjgl/demo/stb/**" if:set="test.stb"/>
 
             <include name="org/lwjgl/demo/system/jawt/**" if:set="test.jawt"/>
-            <include name="org/lwjgl/demo/system/linux/liburing/**" if:set="platform.linux"/>
+            <include name="org/lwjgl/demo/system/linux/liburing/**"/>
 
             <include name="org/lwjgl/demo/util/*.java"/>
             <include name="org/lwjgl/demo/util/freetype/**" if:true="${binding.freetype}"/>

diff --git a/config/cli/classpath.args b/config/cli/classpath.args
@@ -49,6 +49,10 @@ bin/classes/test:\
 bin/classes/samples:\
 modules/samples/src/test/resources:\
 bin/libs/java/testng.jar:\
+bin/libs/java/jcommander.jar:\
+bin/libs/java/jquery.jar:\
+bin/libs/java/slf4j-api.jar:\
+bin/libs/java/slf4j-jdk14.jar:\
 bin/libs/java/joml.jar:\
 bin/libs/java/jmh-core.jar:\
 bin/libs/java/commons-math3.jar:\

diff --git a/config/cli/classpath.win.args b/config/cli/classpath.win.args
@@ -49,6 +49,10 @@ bin/classes/test;\
 bin/classes/samples;\
 modules/samples/src/test/resources;\
 bin/libs/java/testng.jar;\
+bin/libs/java/jcommander.jar;\
+bin/libs/java/jquery.jar;\
+bin/libs/java/slf4j-api.jar;\
+bin/libs/java/slf4j-jdk14.jar;\
 bin/libs/java/joml.jar;\
 bin/libs/java/jmh-core.jar;\
 bin/libs/java/commons-math3.jar;\

diff --git a/config/native-image/META-INF/native-image/jni-config.json b/config/native-image/META-INF/native-image/jni-config.json
@@ -2,9 +2,5 @@
 {
   "name":"org.lwjgl.system.CallbackI",
   "methods":[{"name":"callback","parameterTypes":["long","long"] }]
-},
-{
-  "name":"org.lwjgl.system.ThreadLocalUtil",
-  "methods":[{"name":"setupEnvData","parameterTypes":[] }]
 }
 ]
diff --git a/doc/notes/3.3.5.md b/doc/notes/3.3.5.md
@@ -34,3 +34,8 @@ This build includes the following changes:
 - Core: Fixed support for `va_list` parameters.
 
 #### Breaking Changes
+
+- Core: Replaced thread-local storage of `errno/GetLastError()` with virtual output parameters. (#1003)
+  * The `LibCErrno.getErrno()` and `WinBase.getLastError()` methods have been removed.
+  * System calls in `org.lwjgl.system.linux.*`, `org.lwjgl.system.windows.*` and `org.lwjgl.opengl.WGL` now take an optional output parameter for the error code.
+  * This approach is similar to `Linker.Option.CaptureCallState` in Project Panama's FFM API.
diff --git a/modules/generator/src/main/kotlin/org/lwjgl/generator/Functions.kt b/modules/generator/src/main/kotlin/org/lwjgl/generator/Functions.kt
@@ -81,7 +81,8 @@ class Func(
     private fun getNativeParams(
         withExplicitFunctionAddress: Boolean = true,
         withJNIEnv: Boolean = false,
-        withAutoSizeResultParams: Boolean = true
+        withAutoSizeResultParams: Boolean = true,
+        withCaptureCallState: Boolean = true
     ) = parameters.asSequence()
         .let { p -> if (withExplicitFunctionAddress) p else p.filter { it !== EXPLICIT_FUNCTION_ADDRESS } }
         .let { p -> if (withJNIEnv) p else p.filter { it !== JNI_ENV } }
@@ -90,6 +91,7 @@ class Func(
         else
             p.filter { !((it.has<Virtual>() && !it.has<AutoSizeResultParam>()) || (it.isAutoSizeResultOut && hideAutoSizeResultParam)) }
         }
+        .let { p -> if (withCaptureCallState) p else p.filter { !(it === parameters[0] && CaptureCallState.matches(it)) } }
 
     /** Returns a parameter that has the specified ReferenceModifier with the specified reference. Returns null if no such parameter exists. */
     internal inline fun <reified T> getReferenceParam(reference: String)
@@ -176,7 +178,7 @@ class Func(
     internal val hasArrayOverloads
         get() = !has<OffHeapOnly>() && this.parameters
             .count { it.isAutoSizeResultOut }
-            .let { autoSizeResultOutParams -> this.parameters.asSequence().any { it.has<MultiType>() || it.isArrayParameter(autoSizeResultOutParams) } }
+            .let { autoSizeResultOutParams -> this.parameters.asSequence().any { (it.has<MultiType>() || it.isArrayParameter(autoSizeResultOutParams)) && !(it === this.parameters[0] && CaptureCallState.matches(it)) } }
 
     private val ReturnValue.javaMethodType
         get() = this.nativeType.let {
@@ -1874,7 +1876,7 @@ class Func(
         if (nativeClass.callingConvention !== CallingConvention.DEFAULT)
             print("APIENTRY ")
         print("*${nativeName}PROC) (")
-        val nativeParams = getNativeParams(withExplicitFunctionAddress = false, withJNIEnv = true)
+        val nativeParams = getNativeParams(withExplicitFunctionAddress = false, withJNIEnv = true, withCaptureCallState = false)
         if (nativeParams.any()) {
             printList(nativeParams) {
                 it.toNativeType(nativeClass.binding)
@@ -1957,7 +1959,7 @@ class Func(
             getNativeParams(withExplicitFunctionAddress = false)
                 .filter { it.nativeType.castAddressToPointer }
                 .forEach {
-                    val variableType = it.toNativeType(nativeClass.binding, pointerMode = true)
+                    val variableType = it.toNativeType(if (nativeClass.binding == null || (it === parameters[0] && CaptureCallState.matches(it))) null else nativeClass.binding, pointerMode = true)
 
                     print(t)
                     if (it.nativeType is FunctionType && variableType.contains("(*)")) {
@@ -2061,7 +2063,7 @@ class Func(
                     print("(*$JNIENV)->")
                 print(nativeName)
                 if (!has<Macro> { !function }) print('(')
-                printList(getNativeParams(withExplicitFunctionAddress = false, withJNIEnv = true)) { param ->
+                printList(getNativeParams(withExplicitFunctionAddress = false, withJNIEnv = true, withCaptureCallState = false)) { param ->
                     param.nativeType.let {
                         val name = param.name
                         if (it is StructType) {

diff --git a/modules/generator/src/main/kotlin/org/lwjgl/generator/ModifiersFunction.kt b/modules/generator/src/main/kotlin/org/lwjgl/generator/ModifiersFunction.kt
@@ -116,7 +116,37 @@ class Code(
     )
 }
 
-val SaveErrno = Code(nativeAfterCall = "${t}saveErrno();")
+enum class CaptureCallState(val param: Parameter, val code: Code) {
+    @Suppress("EnumEntryName")
+    errno(
+        Check(1)..nullable..Parameter(int.p, "_errno", "optionally returns the {@code errno} value after this function is called"),
+        Code(nativeAfterCall = "${t}if (_errno != NULL) *_errno = errno;")
+    ),
+    GetLastError(
+        Check(1)..nullable..Parameter(
+            IntegerType("DWORD", PrimitiveMapping.INT).p,
+            "_GetLastError",
+            "optionally returns the result of {@code GetLastError()} after this function is called"
+        ),
+        Code(nativeAfterCall = "${t}if (_GetLastError != NULL) *_GetLastError = GetLastError();")
+    );
+
+    companion object {
+        internal fun apply(func: Func): Func {
+            if (func.parameters.isNotEmpty()) {
+                when (func.parameters[0]) {
+                    errno.param        -> errno.code..func
+                    GetLastError.param -> GetLastError.code..func
+                }
+            }
+            return func
+        }
+
+        internal fun matches(param: Parameter) =
+            param === errno.param ||
+            param === GetLastError.param
+    }
+}
 
 fun statement(code: String, applyTo: ApplyTo = ApplyTo.BOTH): List<Code.Statement> = arrayListOf(Code.Statement(code, applyTo))
 

diff --git a/modules/generator/src/main/kotlin/org/lwjgl/generator/NativeClass.kt b/modules/generator/src/main/kotlin/org/lwjgl/generator/NativeClass.kt
@@ -832,7 +832,8 @@ class NativeClass internal constructor(
         require(_functions.put(name, func) == null) {
             "The $name function is already defined in ${this@NativeClass.className}."
         }
-        return func
+
+        return CaptureCallState.apply(func)
     }
 
     fun customMethod(method: String) {

diff --git a/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_FCNTL.c b/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_FCNTL.c
@@ -9,55 +9,61 @@
 
 EXTERN_C_ENTER
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_nopen(JNIEnv *__env, jclass clazz, jlong pathnameAddress, jint flags, jint mode) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_nopen(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jlong pathnameAddress, jint flags, jint mode) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     char const *pathname = (char const *)(uintptr_t)pathnameAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)open(pathname, flags, (mode_t)mode);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_nopenat(JNIEnv *__env, jclass clazz, jint dirfd, jlong pathnameAddress, jint flags, jint mode) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_nopenat(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint dirfd, jlong pathnameAddress, jint flags, jint mode) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     char const *pathname = (char const *)(uintptr_t)pathnameAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)openat(dirfd, pathname, flags, (mode_t)mode);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_ncreat(JNIEnv *__env, jclass clazz, jlong pathnameAddress, jint mode) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_ncreat(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jlong pathnameAddress, jint mode) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     char const *pathname = (char const *)(uintptr_t)pathnameAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)creat(pathname, (mode_t)mode);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_fcntl(JNIEnv *__env, jclass clazz, jint fd, jint cmd) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_nfcntl(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint fd, jint cmd) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)fcntl(fd, cmd);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_nfcntli(JNIEnv *__env, jclass clazz, jint fd, jint cmd, jint arg) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_nfcntli(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint fd, jint cmd, jint arg) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)fcntl(fd, cmd, arg);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_nfcntlp(JNIEnv *__env, jclass clazz, jint fd, jint cmd, jlong argAddress) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_FCNTL_nfcntlp(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint fd, jint cmd, jlong argAddress) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     void *arg = (void *)(uintptr_t)argAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)fcntl(fd, cmd, arg);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 

diff --git a/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_MMAN.c b/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_MMAN.c
@@ -9,21 +9,23 @@
 
 EXTERN_C_ENTER
 
-JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_MMAN_mmap(JNIEnv *__env, jclass clazz, jlong addrAddress, jlong length, jint prot, jint flags, jint fd, jlong offset) {
+JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_MMAN_nmmap(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jlong addrAddress, jlong length, jint prot, jint flags, jint fd, jlong offset) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     void *addr = (void *)(uintptr_t)addrAddress;
     jlong __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jlong)(uintptr_t)mmap(addr, (size_t)length, prot, flags, fd, (off_t)offset);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_MMAN_nmunmap(JNIEnv *__env, jclass clazz, jlong addrAddress, jlong length) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_MMAN_nmunmap(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jlong addrAddress, jlong length) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     void *addr = (void *)(uintptr_t)addrAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)munmap(addr, (size_t)length);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 

diff --git a/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_Socket.c b/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_Socket.c
@@ -9,11 +9,12 @@
 
 EXTERN_C_ENTER
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_Socket_socket(JNIEnv *__env, jclass clazz, jint __domain, jint __type, jint __protocol) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_Socket_nsocket(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint __domain, jint __type, jint __protocol) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)socket(__domain, __type, __protocol);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 

diff --git a/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_Stat.c b/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_Stat.c
@@ -9,22 +9,24 @@
 
 EXTERN_C_ENTER
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_Stat_nstat(JNIEnv *__env, jclass clazz, jlong __fileAddress, jlong __bufAddress) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_Stat_nstat(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jlong __fileAddress, jlong __bufAddress) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     char const *__file = (char const *)(uintptr_t)__fileAddress;
     struct stat *__buf = (struct stat *)(uintptr_t)__bufAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)stat(__file, __buf);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_Stat_nfstat(JNIEnv *__env, jclass clazz, jint __fd, jlong __bufAddress) {
+JNIEXPORT jint JNICALL Java_org_lwjgl_system_linux_Stat_nfstat(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint __fd, jlong __bufAddress) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     struct stat *__buf = (struct stat *)(uintptr_t)__bufAddress;
     jint __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jint)fstat(__fd, __buf);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 

diff --git a/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_UIO.c b/modules/lwjgl/core/src/generated/c/linux/org_lwjgl_system_linux_UIO.c
@@ -9,59 +9,65 @@
 
 EXTERN_C_ENTER
 
-JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_nreadv(JNIEnv *__env, jclass clazz, jint __fd, jlong __iovecAddress, jint __count) {
+JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_nreadv(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint __fd, jlong __iovecAddress, jint __count) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     struct iovec const *__iovec = (struct iovec const *)(uintptr_t)__iovecAddress;
     jlong __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jlong)readv(__fd, __iovec, __count);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_nwritev(JNIEnv *__env, jclass clazz, jint __fd, jlong __iovecAddress, jint __count) {
+JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_nwritev(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint __fd, jlong __iovecAddress, jint __count) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     struct iovec const *__iovec = (struct iovec const *)(uintptr_t)__iovecAddress;
     jlong __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jlong)writev(__fd, __iovec, __count);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_npreadv(JNIEnv *__env, jclass clazz, jint __fd, jlong __iovecAddress, jint __count, jlong __offset) {
+JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_npreadv(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint __fd, jlong __iovecAddress, jint __count, jlong __offset) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     struct iovec const *__iovec = (struct iovec const *)(uintptr_t)__iovecAddress;
     jlong __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jlong)preadv(__fd, __iovec, __count, (off_t)__offset);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_npwritev(JNIEnv *__env, jclass clazz, jint __fd, jlong __iovecAddress, jint __count, jlong __offset) {
+JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_npwritev(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint __fd, jlong __iovecAddress, jint __count, jlong __offset) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     struct iovec const *__iovec = (struct iovec const *)(uintptr_t)__iovecAddress;
     jlong __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jlong)pwritev(__fd, __iovec, __count, (off_t)__offset);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_nprocess_1vm_1readv(JNIEnv *__env, jclass clazz, jint __pid, jlong __lvecAddress, jlong __liovcnt, jlong __rvecAddress, jlong __riovcnt, jlong __flags) {
+JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_nprocess_1vm_1readv(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint __pid, jlong __lvecAddress, jlong __liovcnt, jlong __rvecAddress, jlong __riovcnt, jlong __flags) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     struct iovec const *__lvec = (struct iovec const *)(uintptr_t)__lvecAddress;
     struct iovec const *__rvec = (struct iovec const *)(uintptr_t)__rvecAddress;
     jlong __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jlong)process_vm_readv((pid_t)__pid, __lvec, (unsigned long int)__liovcnt, __rvec, (unsigned long int)__riovcnt, (unsigned long int)__flags);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }
 
-JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_nprocess_1vm_1writev(JNIEnv *__env, jclass clazz, jint __pid, jlong __lvecAddress, jlong __liovcnt, jlong __rvecAddress, jlong __riovcnt, jlong __flags) {
+JNIEXPORT jlong JNICALL Java_org_lwjgl_system_linux_UIO_nprocess_1vm_1writev(JNIEnv *__env, jclass clazz, jlong _errnoAddress, jint __pid, jlong __lvecAddress, jlong __liovcnt, jlong __rvecAddress, jlong __riovcnt, jlong __flags) {
+    int *_errno = (int *)(uintptr_t)_errnoAddress;
     struct iovec const *__lvec = (struct iovec const *)(uintptr_t)__lvecAddress;
     struct iovec const *__rvec = (struct iovec const *)(uintptr_t)__rvecAddress;
     jlong __result;
     UNUSED_PARAMS(__env, clazz)
     __result = (jlong)process_vm_writev((pid_t)__pid, __lvec, (unsigned long int)__liovcnt, __rvec, (unsigned long int)__riovcnt, (unsigned long int)__flags);
-    saveErrno();
+    if (_errno != NULL) *_errno = errno;
     return __result;
 }