Cygwin: fenv.h: Add feature test macros, fix values

- feenableexcept,fedisableexcept, fegetexcept are GNU-only
- fegetprec, fesetprec are Solaris, use __MISC_VISIBLE
- _feinitialise is Cygwin-internal only
- Replace self-named FP precision values to Solaris values
- Document fegetprec, fesetprec as Solaris functions, not as GNU
  functions

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

3 files changed, 35 insertions, 27 deletions

diff --git a/winsup/cygwin/fenv.cc b/winsup/cygwin/fenv.cc
index 3adc8a9..396f98a 100644
--- a/winsup/cygwin/fenv.cc
+++ b/winsup/cygwin/fenv.cc
@@ -401,7 +401,7 @@ fesetprec (int prec)
   unsigned short cw;
 
   /* Will succeed for any valid value of the input parameter.  */
-  if (prec < FE_SINGLEPREC || prec > FE_EXTENDEDPREC)
+  if (prec < FE_FLTPREC || prec > FE_LDBLPREC)
     return EINVAL;
 
   /* Get control word.  */
diff --git a/winsup/cygwin/include/fenv.h b/winsup/cygwin/include/fenv.h
index 7ce3a93..a355c47 100644
--- a/winsup/cygwin/include/fenv.h
+++ b/winsup/cygwin/include/fenv.h
@@ -106,11 +106,13 @@ typedef __uint32_t fexcept_t;
 #define FE_TOWARDZERO	(3)
 #define FE_UPWARD	(2)
 
-/*  Precision bit values.  Not defined by Posix, but follow logically.  */
-#define FE_SINGLEPREC	(0)
-#define FE_RESERVEDPREC	(1)
-#define FE_DOUBLEPREC	(2)
-#define FE_EXTENDEDPREC	(3)
+/* Precision values defined by Solaris, the only known system actually
+   implementing fegetprec/fesetprec. */
+#ifdef __MISC_VISIBLE /* FIXME? */
+#define FE_FLTPREC	(0)
+#define FE_DBLPREC	(2)
+#define FE_LDBLPREC	(3)
+#endif
 
 /*  The <fenv.h> header shall define the following constant, which
    represents the default floating-point environment (that is, the one
@@ -138,30 +140,36 @@ extern const fenv_t *_fe_nomask_env;
 
 /*  The following shall be declared as functions and may also be
    defined as macros. Function prototypes shall be provided.  */
-extern int feclearexcept (int excepts);
-extern int fegetexceptflag (fexcept_t *flagp, int excepts);
-extern int feraiseexcept (int excepts);
-extern int fesetexceptflag (const fexcept_t *flagp, int excepts);
-extern int fetestexcept (int excepts);
+extern int feclearexcept (int __excepts);
+extern int fegetexceptflag (fexcept_t *__flagp, int __excepts);
+extern int feraiseexcept (int __excepts);
+extern int fesetexceptflag (const fexcept_t *__flagp, int __excepts);
+extern int fetestexcept (int __excepts);
 extern int fegetround (void);
-extern int fesetround (int round);
-extern int fegetenv (fenv_t *envp);
-extern int feholdexcept (fenv_t *envp);
-extern int fesetenv (const fenv_t *envp);
-extern int feupdateenv (const fenv_t *envp);
-
-/* These are not defined in Posix, but make sense by obvious extension.  */
-extern int fegetprec (void);
-extern int fesetprec (int prec);
-
-/* This is Cygwin-custom, not from the standard, for use in the Cygwin CRT.  */
-extern void _feinitialise (void);
+extern int fesetround (int __round);
+extern int fegetenv (fenv_t *__envp);
+extern int feholdexcept (fenv_t *__envp);
+extern int fesetenv (const fenv_t *__envp);
+extern int feupdateenv (const fenv_t *__envp);
 
+#if __GNU_VISIBLE
 /* These are GNU extensions defined in glibc.  */
-extern int feenableexcept (int excepts);
-extern int fedisableexcept (int excepts);
+extern int feenableexcept (int __excepts);
+extern int fedisableexcept (int __excepts);
 extern int fegetexcept (void);
+#endif
+
+/* FIXME, what guard shall we use for Solaris extensions? */
+#if __MISC_VISIBLE
+/* These are defined in Solaris libm.a */
+extern int fegetprec (void);
+extern int fesetprec (int __prec);
+#endif
 
+#ifdef __INSIDE_CYGWIN__
+/* This is Cygwin-custom, not from the standard, for use in the Cygwin CRT.  */
+extern void _feinitialise ();
+#endif
 
 #ifdef __cplusplus
 }
diff --git a/winsup/doc/posix.xml b/winsup/doc/posix.xml
index 0755bed..d49cf55 100644
--- a/winsup/doc/posix.xml
+++ b/winsup/doc/posix.xml
@@ -1319,8 +1319,6 @@ also IEEE Std 1003.1-2008 (POSIX.1-2008).</para>
     fedisableexcept
     feenableexcept
     fegetexcept
-    fegetprec
-    fesetprec
     ffsl
     ffsll
     fgets_unlocked
@@ -1443,6 +1441,8 @@ also IEEE Std 1003.1-2008 (POSIX.1-2008).</para>
     acltotext
     endmntent
     facl
+    fegetprec
+    fesetprec
     futimesat
     getmntent
     memalign