<fenv.h>: documentation, and __INTRODUCED_IN removal.
Now the NDK doesn't support API levels below 21, we don't actually need
the different arm32 vs x86 annotations. In general we haven't been
removing this historical information because it might be interesting to
someone, and there's no real reason to remove it, but we've had
versioner bugs recently with these more complex cases.
Test: treehugger
Change-Id: I9460109a2648b9d05d7e21e397935293d3fea8eb
diff --git a/libc/include/fenv.h b/libc/include/fenv.h
index 6e8ea57..f7dcc8e 100644
--- a/libc/include/fenv.h
+++ b/libc/include/fenv.h
@@ -29,6 +29,11 @@
#pragma once
+/**
+ * @file fenv.h
+ * @brief Floating-point environment.
+ */
+
#include <sys/cdefs.h>
#if defined(__aarch64__) || defined(__arm__)
@@ -43,33 +48,135 @@
__BEGIN_DECLS
-int feclearexcept(int __exceptions) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int fegetexceptflag(fexcept_t* _Nonnull __flag_ptr, int __exceptions) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int feraiseexcept(int __exceptions) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int fesetexceptflag(const fexcept_t* _Nonnull __flag_ptr, int __exceptions) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int fetestexcept(int __exceptions) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
+/**
+ * [feclearexcept(3)](http://man7.org/linux/man-pages/man3/feclearexcept.3.html)
+ * clears the given `exceptions` in hardware.
+ *
+ * Returns 0 on success, and returns non-zero on failure.
+ */
+int feclearexcept(int __exceptions);
-int fegetround(void) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int fesetround(int __rounding_mode) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
+/**
+ * [fegetexceptflag(3)](http://man7.org/linux/man-pages/man3/fegetexceptflag.3.html)
+ * copies the state of the given `exceptions` from hardware into `*flag_ptr`.
+ * See fesetexceptflag().
+ *
+ * Returns 0 on success, and returns non-zero on failure.
+ */
+int fegetexceptflag(fexcept_t* _Nonnull __flag_ptr, int __exceptions);
-int fegetenv(fenv_t* _Nonnull __env) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int feholdexcept(fenv_t* _Nonnull __env) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int fesetenv(const fenv_t* _Nonnull __env) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int feupdateenv(const fenv_t* _Nonnull __env) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
+/**
+ * [feraiseexcept(3)](http://man7.org/linux/man-pages/man3/feraiseexcept.3.html)
+ * raises the given `exceptions` in hardware.
+ *
+ * Returns 0 on success, and returns non-zero on failure.
+ */
+int feraiseexcept(int __exceptions);
-int feenableexcept(int __exceptions) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int fedisableexcept(int __exceptions) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
-int fegetexcept(void) __INTRODUCED_IN_ARM(21) __INTRODUCED_IN_X86(9);
+/**
+ * [fesetexceptflag(3)](http://man7.org/linux/man-pages/man3/fesetexceptflag.3.html)
+ * copies the state of the given `exceptions` from `*flag_ptr` into hardware.
+ * See fesetexceptflag().
+ *
+ * Returns 0 on success, and returns non-zero on failure.
+ */
+int fesetexceptflag(const fexcept_t* _Nonnull __flag_ptr, int __exceptions);
-/*
- * The following constant represents the default floating-point environment
- * (that is, the one installed at program startup) and has type pointer to
- * const-qualified fenv_t.
+/**
+ * [fetestexcept(3)](http://man7.org/linux/man-pages/man3/fetestexcept.3.html)
+ * tests whether the given `exceptions` are set in hardware.
+ *
+ * Returns the currently-set subset of `exceptions`.
+ */
+int fetestexcept(int __exceptions);
+
+/**
+ * [fegetround(3)](http://man7.org/linux/man-pages/man3/fegetround.3.html)
+ * returns the current rounding mode.
+ *
+ * Returns the rounding mode on success, and returns a negative value on failure.
+ */
+int fegetround(void);
+
+/**
+ * [fesetround(3)](http://man7.org/linux/man-pages/man3/fesetround.3.html)
+ * sets the current rounding mode.
+ *
+ * Returns 0 on success, and returns non-zero on failure.
+ */
+int fesetround(int __rounding_mode);
+
+/**
+ * [fegetenv(3)](http://man7.org/linux/man-pages/man3/fegetenv.3.html)
+ * gets the current floating-point environment. See fesetenv().
+ *
+ * Returns 0 on success, and returns non-zero on failure.
+ */
+int fegetenv(fenv_t* _Nonnull __env);
+
+/**
+ * [feholdexcept(3)](http://man7.org/linux/man-pages/man3/feholdexcept.3.html)
+ * gets the current floating-point environment, clears the status flags, and
+ * ignores floating point exceptions. See fesetenv()/feupdateenv().
+ *
+ * Returns 0 on success, and returns non-zero on failure.
+ */
+int feholdexcept(fenv_t* _Nonnull __env);
+
+/**
+ * [fesetenv(3)](http://man7.org/linux/man-pages/man3/fesetenv.3.html)
+ * sets the current floating-point environment. See fegetenv().
+ *
+ * Returns 0 on success, and returns non-zero on failure.
+ */
+int fesetenv(const fenv_t* _Nonnull __env);
+
+/**
+ * [feupdateenv(3)](http://man7.org/linux/man-pages/man3/feupdateenv.3.html)
+ * sets the current floating-point environment to `*env` but with currently-raised
+ * exceptions still raised. See fesetenv().
+ *
+ * Returns 0 on success, and returns non-zero on failure.
+ */
+int feupdateenv(const fenv_t* _Nonnull __env);
+
+/**
+ * [feenableexcept(3)](http://man7.org/linux/man-pages/man3/feenableexcept.3.html)
+ * sets the given `exceptions` to trap, if the hardware supports it. This is not
+ * generally useful on Android, because only x86/x86-64 can trap.
+ *
+ * Returns the previous set of enabled exceptions on success, and returns -1 on failure.
+ */
+int feenableexcept(int __exceptions);
+
+/**
+ * [fedisableexcept(3)](http://man7.org/linux/man-pages/man3/fedisableexcept.3.html)
+ * sets the given `exceptions` to not trap, if the hardware supports it. This is not
+ * generally useful on Android, because only x86/x86-64 can trap.
+ *
+ * Returns the previous set of enabled exceptions on success, and returns -1 on failure.
+ */
+int fedisableexcept(int __exceptions);
+
+/**
+ * [fegetexcept(3)](http://man7.org/linux/man-pages/man3/fegetexcept.3.html)
+ * returns the exceptions that currently trap. This is not generally useful on
+ * Android, because only x86/x86-64 can trap.
+ *
+ * Returns the exceptions that currently trap.
+ */
+int fegetexcept(void);
+
+/** See FE_DFL_ENV. */
+extern const fenv_t __fe_dfl_env;
+
+/**
+ * Constant representing the default floating-point environment
+ * (that is, the one installed at program startup).
*
* It can be used as an argument to the functions that manage the floating-point
* environment, namely fesetenv() and feupdateenv().
*/
-extern const fenv_t __fe_dfl_env;
#define FE_DFL_ENV (&__fe_dfl_env)
__END_DECLS