From 5ff263e65f0dade0458d23fb78dfea12c94eb2be Mon Sep 17 00:00:00 2001
From: Martin <noone@nowhere.com>
Date: Thu, 27 Aug 2015 21:51:30 +0200
Subject: [PATCH] Visual Studio 2015: exploit C99-conformant (v)snprintf in
 core.stdc.stdio

---
 src/core/stdc/stdio.d | 36 +++++++++++++++----------------
 src/rt/stdio_msvc.c   | 49 +++++++++++++++++++------------------------
 2 files changed, 39 insertions(+), 46 deletions(-)

diff --git a/src/core/stdc/stdio.d b/src/core/stdc/stdio.d
index ae2966a8a5..acdc57f83e 100644
--- a/src/core/stdc/stdio.d
+++ b/src/core/stdc/stdio.d
@@ -71,7 +71,7 @@ else version( CRuntime_Microsoft )
         FOPEN_MAX    = 20,
         ///
         FILENAME_MAX = 260,
-        ///
+        /// Actually int.max since Visual Studio 2015.
         TMP_MAX      = 32767,
         ///
         _SYS_OPEN    = 20,      // non-standard
@@ -79,11 +79,11 @@ else version( CRuntime_Microsoft )
 
     ///
     enum int     _NFILE     = 512;       // non-standard
-    ///
+    /// Removed since Visual Studio 2015.
     enum string  _P_tmpdir  = "\\"; // non-standard
-    ///
+    /// Removed since Visual Studio 2015.
     enum wstring _wP_tmpdir = "\\"; // non-standard
-    ///
+    /// Actually 260 since Visual Studio 2015.
     enum int     L_tmpnam   = _P_tmpdir.length + 12;
 }
 else version( CRuntime_Glibc )
@@ -543,23 +543,23 @@ else version( CRuntime_Microsoft )
         _IOLBF   = 0x40,
         ///
         _IONBF   = 4,
-        ///
+        /// Removed since Visual Studio 2015.
         _IOREAD  = 1,     // non-standard
-        ///
+        /// Removed since Visual Studio 2015.
         _IOWRT   = 2,     // non-standard
-        ///
+        /// Removed since Visual Studio 2015.
         _IOMYBUF = 8,     // non-standard
-        ///
+        /// Removed since Visual Studio 2015.
         _IOEOF   = 0x10,  // non-standard
-        ///
+        /// Removed since Visual Studio 2015.
         _IOERR   = 0x20,  // non-standard
-        ///
+        /// Removed since Visual Studio 2015.
         _IOSTRG  = 0x40,  // non-standard
-        ///
+        /// Removed since Visual Studio 2015.
         _IORW    = 0x80,  // non-standard
-        ///
+        /// Removed since Visual Studio 2015.
         _IOAPP   = 0x200, // non-standard
-        ///
+        /// Removed since Visual Studio 2015.
         _IOAPPEND = 0x200, // non-standard
     }
 
@@ -941,19 +941,19 @@ else version( CRuntime_Microsoft )
     ///
     pure int  fileno(FILE* stream);
   }
+
   ///
-    int   _snprintf(char* s, size_t n, in char* fmt, ...);
+    int _snprintf(char* s, size_t n, in char* format, ...);
     ///
-    alias _snprintf snprintf;
+    int  snprintf(char* s, size_t n, in char* format, ...);
 
     ///
-    int   _vsnprintf(char* s, size_t n, in char* format, va_list arg);
+    int _vsnprintf(char* s, size_t n, in char* format, va_list arg);
     ///
-    alias _vsnprintf vsnprintf;
+    int  vsnprintf(char* s, size_t n, in char* format, va_list arg);
 
     ///
     int _fputc_nolock(int c, FILE *fp);
-
     ///
     int _fgetc_nolock(FILE *fp);
 
diff --git a/src/rt/stdio_msvc.c b/src/rt/stdio_msvc.c
index 92f0f9b7c6..a81042643f 100644
--- a/src/rt/stdio_msvc.c
+++ b/src/rt/stdio_msvc.c
@@ -53,12 +53,21 @@ void init_msvc()
         FILE* fp = __iob_func();
         stdin = fp;
         stdout = fp + 1;
-        stderr = fp + 1;
+        stderr = fp + 2;
     }
     if (&_set_output_format != (void*) &_nullfunc)
-        _set_output_format(1);
+    {
+        const int _TWO_DIGIT_EXPONENT = 1;
+        _set_output_format(_TWO_DIGIT_EXPONENT);
+    }
 }
 
+// VS2015+ provides C99-conformant (v)snprintf functions, so weakly
+// link to legacy _(v)snprintf (not C99-conformant!) for VS2013- only
+
+#pragma comment(linker, "/alternatename:snprintf=_snprintf")
+#pragma comment(linker, "/alternatename:vsnprintf=_vsnprintf")
+
 // VS2013- implements these functions as macros, VS2015+ provides symbols
 
 #pragma comment(linker, "/alternatename:_fputc_nolock=_msvc_fputc_nolock")
@@ -70,13 +79,13 @@ void init_msvc()
 #pragma comment(linker, "/alternatename:fileno=_msvc_fileno")
 
 // VS2013- helper functions
-int _filbuf(FILE *fp);
-int _flsbuf(int c, FILE *fp);
+int _filbuf(FILE* fp);
+int _flsbuf(int c, FILE* fp);
 
 #pragma comment(linker, "/alternatename:_filbuf=_nullfunc")
 #pragma comment(linker, "/alternatename:_flsbuf=_nullfunc")
 
-int _msvc_fputc_nolock(int c, FILE *fp)
+int _msvc_fputc_nolock(int c, FILE* fp)
 {
     fp->_cnt = fp->_cnt - 1;
     if (fp->_cnt >= 0)
@@ -89,7 +98,7 @@ int _msvc_fputc_nolock(int c, FILE *fp)
         return _flsbuf(c, fp);
 }
 
-int _msvc_fgetc_nolock(FILE *fp)
+int _msvc_fgetc_nolock(FILE* fp)
 {
     fp->_cnt = fp->_cnt - 1;
     if (fp->_cnt >= 0)
@@ -104,38 +113,22 @@ int _msvc_fgetc_nolock(FILE *fp)
 
 enum
 {
-    _IOFBF   = 0,
-    _IOLBF   = 0x40,
-    _IONBF   = 4,
-    _IOREAD  = 1,     // non-standard
-    _IOWRT   = 2,     // non-standard
-    _IOMYBUF = 8,     // non-standard
-    _IOEOF   = 0x10,  // non-standard
-    _IOERR   = 0x20,  // non-standard
-    _IOSTRG  = 0x40,  // non-standard
-    _IORW    = 0x80,  // non-standard
-    _IOAPP   = 0x200, // non-standard
-    _IOAPPEND = 0x200, // non-standard
+    SEEK_SET = 0,
+    _IOEOF   = 0x10,
+    _IOERR   = 0x20
 };
 
-enum
-{
-    SEEK_SET,
-    SEEK_CUR,
-    SEEK_END
-};
-
-int fseek(FILE *fp, long off, int whence);
+int fseek(FILE* fp, long off, int whence);
 
 void _msvc_rewind(FILE* stream)
 {
     fseek(stream, 0L, SEEK_SET);
     stream->_flag = stream->_flag & ~_IOERR;
 }
-///
+
 void _msvc_clearerr(FILE* stream)
 {
-    stream->_flag = stream->_flag & ~(_IOERR|_IOEOF);
+    stream->_flag = stream->_flag & ~(_IOERR | _IOEOF);
 }
 
 int  _msvc_feof(FILE* stream)