sched/arch/libc: make task_fork() optional

task_fork() is a NuttX extension, not POSIX, and a configuration that does not call it has no reason to carry it. Add CONFIG_TASK_FORK to leave it out. It depends on ARCH_HAVE_TASK_FORK and defaults to y, so it is enabled exactly where fork() existed before the split and no configuration loses the primitive by upgrading. ARCH_HAVE_TASK_FORK keeps its meaning -- the architecture *can* clone the calling task -- and the new symbol says whether this build wants it. Everything that provides task_fork() moves to the new symbol: the declaration in sched.h, up_task_fork() in arch.h, the two .csv entries that generate the system call stub and proxy, the syscall_lookup.h table entry, the architecture entry points, and the build rules for the files that hold them. FORK_IS_TASK_FORK now depends on TASK_FORK rather than ARCH_HAVE_TASK_FORK. Aliasing fork() to a task_fork() that was not built would not link. vfork() and fork() are untouched; each is still selected on its own, and task_fork.c, lib_fork.c and the architecture's fork file are still built when any one of the three is present. Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com> Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-09 22:45:08 +00:00 · 2026-07-30 11:03:54 +02:00 · 2026-07-30 11:03:54 +02:00 · 9b787d42b2
commit 9b787d42b2
parent ca8287e690
32 changed files with 70 additions and 46 deletions
--- a/Documentation/guides/fork_vfork_migration.rst
+++ b/Documentation/guides/fork_vfork_migration.rst
@ -42,7 +42,7 @@ There are now three distinct primitives:
   * - ``task_fork()``
     - child shares memory, private stack copy
     - runs concurrently
-     - ``CONFIG_ARCH_HAVE_TASK_FORK`` -- exactly where ``fork()`` existed
+     - ``CONFIG_TASK_FORK`` -- on by default exactly where ``fork()`` existed
       before

 ``task_fork()`` is the old behaviour under an honest name.  Nothing was lost.
@ -122,6 +122,13 @@ Configuration symbols
   Inherits exactly the ``select`` lines that ``ARCH_HAVE_FORK`` used to have,
   so no configuration that had ``fork()`` loses the machinery.

+``CONFIG_TASK_FORK``
+   Provide ``task_fork()``.  Defaults to ``y`` wherever
+   ``ARCH_HAVE_TASK_FORK`` is selected, so no configuration that had ``fork()``
+   loses the primitive.  Turn it off to leave a NuttX extension out of a build
+   that does not call it; the architecture entry point, the system call and the
+   libc stub go with it.  ``vfork()`` and ``fork()`` are unaffected.
+
 ``CONFIG_ARCH_HAVE_VFORK``
   Hidden.  The architecture can implement POSIX ``vfork()``.

--- a/Documentation/reference/user/01_task_control.rst
+++ b/Documentation/reference/user/01_task_control.rst
@ -435,10 +435,10 @@ Functions
  under the name ``fork()`` before these three interfaces were separated, and
  it is preserved here under an honest name so that nothing is lost.

-     NOTE: available where ``CONFIG_ARCH_HAVE_TASK_FORK`` is selected, which
-     is exactly the set of configurations that had ``fork()`` before the
-     split.  New code should prefer :c:func:`pthread_create`, which is the
-     same memory relationship spelled clearly, or :c:func:`posix_spawn`;
+     NOTE: available where ``CONFIG_TASK_FORK`` is enabled, which defaults to
+     the set of configurations that had ``fork()`` before the split, and can
+     be turned off.  New code should prefer :c:func:`pthread_create`, which
+     is the same memory relationship spelled clearly, or :c:func:`posix_spawn`;
     ``task_fork()`` exists to give the historical behaviour a truthful name,
     not to recommend it.

--- a/arch/Kconfig
+++ b/arch/Kconfig
@ -534,10 +534,27 @@ config ARCH_HAVE_FORK
 		Where this is not selected fork() is not provided at all, and code
 		that calls it fails to build -- see FORK_IS_TASK_FORK.

+config TASK_FORK
+	bool "Provide task_fork()"
+	default y
+	depends on ARCH_HAVE_TASK_FORK
+	---help---
+		Provide task_fork(), which clones the calling task:  the child shares
+		the parent's .data/.bss/heap, runs on a private copy of the parent's
+		stack, and runs concurrently with the parent.  This is the historical
+		NuttX fork() behaviour under its own name.  It is not POSIX, and it is
+		neither fork() nor vfork().
+
+		Disable this to leave it out where nothing calls it.  The saving is
+		small -- the architecture's entry point, the system call and the libc
+		stub -- but the primitive is a NuttX extension, so a configuration
+		that does not want it need not carry it.  vfork() and fork() are
+		unaffected; each is selected on its own.
+
 config FORK_IS_TASK_FORK
 	bool "Provide fork() as an alias for task_fork() (legacy)"
 	default n
-	depends on ARCH_HAVE_TASK_FORK && !ARCH_HAVE_FORK
+	depends on TASK_FORK && !ARCH_HAVE_FORK
 	---help---
 		Provide fork() on configurations that cannot implement POSIX fork()
 		semantics, by aliasing it to task_fork().
--- a/arch/arm/src/common/gnu/fork.S
+++ b/arch/arm/src/common/gnu/fork.S
@ -78,7 +78,7 @@
 *
 ****************************************************************************/

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 	.globl	up_task_fork
 #ifdef __ghs__
 	.type	up_task_fork, $function
--- a/arch/arm/src/common/iar/fork.S
+++ b/arch/arm/src/common/iar/fork.S
@ -39,7 +39,7 @@
 * Public Symbols
 ****************************************************************************/

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 	PUBLIC	up_task_fork
 #endif
 #ifdef CONFIG_ARCH_HAVE_VFORK
@ -100,7 +100,7 @@

 	THUMB

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 up_task_fork:
 	movs		r2, #FORK_TYPE_TASK
 	b		arm_fork_common
--- a/arch/arm64/src/common/arm64_fork_func.S
+++ b/arch/arm64/src/common/arm64_fork_func.S
@ -84,7 +84,7 @@
 *
 ****************************************************************************/

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 GTEXT(up_task_fork)
 SECTION_FUNC(text, up_task_fork)
    mov    x1, #FORK_TYPE_TASK
--- a/arch/mips/src/mips32/fork.S
+++ b/arch/mips/src/mips32/fork.S
@ -93,7 +93,7 @@
 	.set	micromips
 #endif

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 	.globl	up_task_fork
 	.type	up_task_fork, function
 	.ent	up_task_fork
--- a/arch/risc-v/src/common/CMakeLists.txt
+++ b/arch/risc-v/src/common/CMakeLists.txt
@ -86,7 +86,7 @@ if(CONFIG_STACK_COLORATION)
  list(APPEND SRCS riscv_checkstack.c)
 endif()

-if(CONFIG_ARCH_HAVE_TASK_FORK
+if(CONFIG_TASK_FORK
   OR CONFIG_ARCH_HAVE_VFORK
   OR CONFIG_ARCH_HAVE_FORK)
  list(APPEND SRCS fork.S riscv_fork.c)
--- a/arch/risc-v/src/common/Make.defs
+++ b/arch/risc-v/src/common/Make.defs
@ -86,7 +86,7 @@ ifeq ($(CONFIG_STACK_COLORATION),y)
 CMN_CSRCS += riscv_checkstack.c
 endif

-ifneq ($(CONFIG_ARCH_HAVE_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
+ifneq ($(CONFIG_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
 CMN_ASRCS += fork.S
 CMN_CSRCS += riscv_fork.c
 endif
--- a/arch/risc-v/src/common/fork.S
+++ b/arch/risc-v/src/common/fork.S
@ -39,7 +39,7 @@

  .file  "fork.S"
  .globl riscv_fork
-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
  .globl up_task_fork
 #endif
 #ifdef CONFIG_ARCH_HAVE_VFORK
@ -89,7 +89,7 @@
 *
 ****************************************************************************/

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 .type up_task_fork, function

 up_task_fork:
--- a/arch/risc-v/src/common/riscv_fork.c
+++ b/arch/risc-v/src/common/riscv_fork.c
@ -41,7 +41,7 @@

 #include "sched/sched.h"

-#if defined(CONFIG_ARCH_HAVE_TASK_FORK) || defined(CONFIG_ARCH_HAVE_VFORK) || \
+#if defined(CONFIG_TASK_FORK) || defined(CONFIG_ARCH_HAVE_VFORK) || \
    defined(CONFIG_ARCH_HAVE_FORK)

 /****************************************************************************
@ -351,5 +351,5 @@ pid_t riscv_fork(const struct fork_s *context, int type)
 }

 #endif /* CONFIG_LIB_SYSCALL */
-#endif /* CONFIG_ARCH_HAVE_TASK_FORK || CONFIG_ARCH_HAVE_VFORK ||
+#endif /* CONFIG_TASK_FORK || CONFIG_ARCH_HAVE_VFORK ||
        * CONFIG_ARCH_HAVE_FORK */
--- a/arch/sim/src/Makefile
+++ b/arch/sim/src/Makefile
@ -95,7 +95,7 @@ ifeq ($(CONFIG_SCHED_BACKTRACE),y)
 CSRCS += sim_backtrace.c
 endif

-ifneq ($(CONFIG_ARCH_HAVE_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
+ifneq ($(CONFIG_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
 CSRCS += sim_fork.c
 endif

--- a/arch/sim/src/sim/CMakeLists.txt
+++ b/arch/sim/src/sim/CMakeLists.txt
@ -82,7 +82,7 @@ if(CONFIG_SCHED_BACKTRACE)
  list(APPEND SRCS sim_backtrace.c)
 endif()

-if(CONFIG_ARCH_HAVE_TASK_FORK
+if(CONFIG_TASK_FORK
   OR CONFIG_ARCH_HAVE_VFORK
   OR CONFIG_ARCH_HAVE_FORK)
  list(APPEND SRCS sim_fork.c)
--- a/arch/sim/src/sim/sim_fork.c
+++ b/arch/sim/src/sim/sim_fork.c
@ -190,7 +190,7 @@ static pid_t sim_fork_internal(const xcpt_reg_t *context, int type)
 *
 ****************************************************************************/

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 pid_t sim_task_fork(const xcpt_reg_t *context)
 {
  return sim_fork_internal(context, FORK_TYPE_TASK);
--- a/arch/sim/src/sim/sim_fork_arm.S
+++ b/arch/sim/src/sim/sim_fork_arm.S
@ -99,7 +99,7 @@

 	.text

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 	.globl	up_task_fork
 	.type	up_task_fork, @function
 up_task_fork:
@ -114,7 +114,7 @@ up_task_fork:
 	add	sp, sp, #XCPTCONTEXT_SIZE
 	bx	lr
 	.size	up_task_fork, . - up_task_fork
-#endif /* CONFIG_ARCH_HAVE_TASK_FORK */
+#endif /* CONFIG_TASK_FORK */

 #ifdef CONFIG_ARCH_HAVE_VFORK
 	.globl	up_vfork
--- a/arch/sim/src/sim/sim_fork_arm64.S
+++ b/arch/sim/src/sim/sim_fork_arm64.S
@ -110,7 +110,7 @@
 	.text
 	.align	4

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 	.globl	SYMBOL(up_task_fork)

 SYMBOL(up_task_fork):
@ -132,7 +132,7 @@ SYMBOL(up_task_fork):
 	ldp		x29, x30, [sp]				/* restore FP/LR register */

 	ret
-#endif /* CONFIG_ARCH_HAVE_TASK_FORK */
+#endif /* CONFIG_TASK_FORK */

 #ifdef CONFIG_ARCH_HAVE_VFORK
 	.globl	SYMBOL(up_vfork)
--- a/arch/sim/src/sim/sim_fork_x86.S
+++ b/arch/sim/src/sim/sim_fork_x86.S
@ -107,7 +107,7 @@

 	.text

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 	.globl	SYMBOL(up_task_fork)
 #ifdef __ELF__
 	.type	SYMBOL(up_task_fork), @function
@ -127,7 +127,7 @@ SYMBOL(up_task_fork):
 #ifdef __ELF__
 	.size	SYMBOL(up_task_fork), . - SYMBOL(up_task_fork)
 #endif
-#endif /* CONFIG_ARCH_HAVE_TASK_FORK */
+#endif /* CONFIG_TASK_FORK */

 #ifdef CONFIG_ARCH_HAVE_VFORK
 	.globl	SYMBOL(up_vfork)
--- a/arch/sim/src/sim/sim_fork_x86_64.S
+++ b/arch/sim/src/sim/sim_fork_x86_64.S
@ -107,7 +107,7 @@

 	.text

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 	.globl	SYMBOL(up_task_fork)
 #ifdef __ELF__
 	.type	SYMBOL(up_task_fork), @function
@ -132,7 +132,7 @@ SYMBOL(up_task_fork):
 #ifdef __ELF__
 	.size	SYMBOL(up_task_fork), . - SYMBOL(up_task_fork)
 #endif
-#endif /* CONFIG_ARCH_HAVE_TASK_FORK */
+#endif /* CONFIG_TASK_FORK */

 #ifdef CONFIG_ARCH_HAVE_VFORK
 	.globl	SYMBOL(up_vfork)
--- a/arch/x86_64/src/common/CMakeLists.txt
+++ b/arch/x86_64/src/common/CMakeLists.txt
@ -34,7 +34,7 @@ set(SRCS
    x86_64_tcbinfo.c
    x86_64_tlb.c)

-if(CONFIG_ARCH_HAVE_TASK_FORK
+if(CONFIG_TASK_FORK
   OR CONFIG_ARCH_HAVE_VFORK
   OR CONFIG_ARCH_HAVE_FORK)
  list(APPEND SRCS x86_64_fork.c fork.S)
--- a/arch/x86_64/src/common/Make.defs
+++ b/arch/x86_64/src/common/Make.defs
@ -29,7 +29,7 @@ CMN_CSRCS += x86_64_getintstack.c  x86_64_initialize.c x86_64_nputs.c
 CMN_CSRCS += x86_64_modifyreg8.c x86_64_modifyreg16.c x86_64_modifyreg32.c
 CMN_CSRCS += x86_64_switchcontext.c x86_64_tlb.c

-ifneq ($(CONFIG_ARCH_HAVE_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
+ifneq ($(CONFIG_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
 CMN_CSRCS += x86_64_fork.c
 CMN_ASRCS += fork.S
 endif
--- a/arch/x86_64/src/common/fork.S
+++ b/arch/x86_64/src/common/fork.S
@ -95,7 +95,7 @@
 * | ......... |
 */

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
    .globl  up_task_fork
    .type   up_task_fork, @function

--- a/include/nuttx/arch.h
+++ b/include/nuttx/arch.h
@ -265,7 +265,7 @@ extern initializer_t _einit[];
 *
 ****************************************************************************/

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 pid_t up_task_fork(void);
 #endif

--- a/include/sched.h
+++ b/include/sched.h
@ -239,7 +239,7 @@ int    task_restart(pid_t pid);
 * posix_spawn().
 */

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 pid_t  task_fork(void);
 #endif

--- a/include/sys/syscall_lookup.h
+++ b/include/sys/syscall_lookup.h
@ -112,7 +112,7 @@ SYSCALL_LOOKUP(nxsem_wait_slow,            1)

 /* The following can be individually enabled */

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
  SYSCALL_LOOKUP(up_task_fork,             0)
 #endif

--- a/libs/libc/libc.csv
+++ b/libs/libc/libc.csv
@ -326,7 +326,7 @@
 "swprintf","wchar.h","","int","FAR wchar_t *","size_t","FAR const wchar_t *","..."
 "sysconf","unistd.h","","long","int"
 "syslog","syslog.h","","void","int","FAR const IPTR char *","..."
-"task_fork","sched.h","!defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_ARCH_HAVE_TASK_FORK)","pid_t"
+"task_fork","sched.h","!defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_TASK_FORK)","pid_t"
 "task_testcancel","sched.h","defined(CONFIG_CANCELLATION_POINTS)","void"
 "task_tls_alloc","nuttx/tls.h","!defined(CONFIG_BUILD_KERNEL) && CONFIG_TLS_TASK_NELEM > 0","int","tls_dtor_t"
 "task_tls_get_value","nuttx/tls.h","CONFIG_TLS_TASK_NELEM > 0","uintptr_t","int"
--- a/libs/libc/unistd/CMakeLists.txt
+++ b/libs/libc/unistd/CMakeLists.txt
@ -102,7 +102,7 @@ if(NOT CONFIG_DISABLE_MOUNTPOINTS)
  list(APPEND SRCS lib_truncate.c lib_posix_fallocate.c)
 endif()

-if(CONFIG_ARCH_HAVE_TASK_FORK
+if(CONFIG_TASK_FORK
   OR CONFIG_ARCH_HAVE_VFORK
   OR CONFIG_ARCH_HAVE_FORK)
  list(APPEND SRCS lib_fork.c)
--- a/libs/libc/unistd/Make.defs
+++ b/libs/libc/unistd/Make.defs
@ -53,7 +53,7 @@ ifneq ($(CONFIG_DISABLE_MOUNTPOINTS),y)
 CSRCS += lib_truncate.c lib_posix_fallocate.c
 endif

-ifneq ($(CONFIG_ARCH_HAVE_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
+ifneq ($(CONFIG_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
 CSRCS += lib_fork.c
 endif

--- a/libs/libc/unistd/lib_fork.c
+++ b/libs/libc/unistd/lib_fork.c
@ -35,7 +35,7 @@
 #include <errno.h>
 #include <nuttx/debug.h>

-#if defined(CONFIG_ARCH_HAVE_TASK_FORK) || defined(CONFIG_ARCH_HAVE_VFORK) || \
+#if defined(CONFIG_TASK_FORK) || defined(CONFIG_ARCH_HAVE_VFORK) || \
    defined(CONFIG_ARCH_HAVE_FORK)

 /****************************************************************************
@ -154,7 +154,7 @@ static void atfork_parent(void)
 *
 ****************************************************************************/

-#ifdef CONFIG_ARCH_HAVE_TASK_FORK
+#ifdef CONFIG_TASK_FORK
 pid_t task_fork(void)
 {
  pid_t pid;
@ -177,7 +177,7 @@ pid_t task_fork(void)

  return pid;
 }
-#endif /* CONFIG_ARCH_HAVE_TASK_FORK */
+#endif /* CONFIG_TASK_FORK */

 /****************************************************************************
 * Name: vfork
@ -280,5 +280,5 @@ pid_t fork(void)
 }
 #endif

-#endif /* CONFIG_ARCH_HAVE_TASK_FORK || CONFIG_ARCH_HAVE_VFORK ||
+#endif /* CONFIG_TASK_FORK || CONFIG_ARCH_HAVE_VFORK ||
        * CONFIG_ARCH_HAVE_FORK */
--- a/sched/task/CMakeLists.txt
+++ b/sched/task/CMakeLists.txt
@ -46,7 +46,7 @@ if(CONFIG_SCHED_HAVE_PARENT)
  list(APPEND SRCS task_getppid.c task_reparent.c)
 endif()

-if(CONFIG_ARCH_HAVE_TASK_FORK
+if(CONFIG_TASK_FORK
   OR CONFIG_ARCH_HAVE_VFORK
   OR CONFIG_ARCH_HAVE_FORK)
  list(APPEND SRCS task_fork.c)
--- a/sched/task/Make.defs
+++ b/sched/task/Make.defs
@ -30,7 +30,7 @@ ifeq ($(CONFIG_SCHED_HAVE_PARENT),y)
 CSRCS += task_getppid.c task_reparent.c
 endif

-ifneq ($(CONFIG_ARCH_HAVE_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
+ifneq ($(CONFIG_TASK_FORK)$(CONFIG_ARCH_HAVE_VFORK)$(CONFIG_ARCH_HAVE_FORK),)
 CSRCS += task_fork.c
 endif

--- a/sched/task/task_fork.c
+++ b/sched/task/task_fork.c
@ -49,7 +49,7 @@
 * built if the architecture can provide any one of them.
 */

-#if defined(CONFIG_ARCH_HAVE_TASK_FORK) || defined(CONFIG_ARCH_HAVE_VFORK) || \
+#if defined(CONFIG_TASK_FORK) || defined(CONFIG_ARCH_HAVE_VFORK) || \
    defined(CONFIG_ARCH_HAVE_FORK)

 /****************************************************************************
@ -649,5 +649,5 @@ void nxtask_abort_fork(FAR struct tcb_s *child, int errcode)
  set_errno(errcode);
 }

-#endif /* CONFIG_ARCH_HAVE_TASK_FORK || CONFIG_ARCH_HAVE_VFORK ||
+#endif /* CONFIG_TASK_FORK || CONFIG_ARCH_HAVE_VFORK ||
        * CONFIG_ARCH_HAVE_FORK */
--- a/syscall/syscall.csv
+++ b/syscall/syscall.csv
@ -199,7 +199,7 @@
 "unlink","unistd.h","!defined(CONFIG_DISABLE_MOUNTPOINT)","int","FAR const char *"
 "unsetenv","stdlib.h","!defined(CONFIG_DISABLE_ENVIRON)","int","FAR const char *"
 "up_fork","nuttx/arch.h","defined(CONFIG_ARCH_HAVE_FORK)","pid_t"
-"up_task_fork","nuttx/arch.h","defined(CONFIG_ARCH_HAVE_TASK_FORK)","pid_t"
+"up_task_fork","nuttx/arch.h","defined(CONFIG_TASK_FORK)","pid_t"
 "up_vfork","nuttx/arch.h","defined(CONFIG_ARCH_HAVE_VFORK)","pid_t"
 "utimens","sys/stat.h","","int","FAR const char *","const struct timespec [2]|FAR const struct timespec *"
 "wait","sys/wait.h","defined(CONFIG_SCHED_WAITPID) && defined(CONFIG_SCHED_HAVE_PARENT)","pid_t","FAR int *"