Use COLUMNS environment variable for console width

projects/tests/catch.hpp

@@ -3048,17 +3048,36 @@ namespace STITCH_TBC_TEXT_FORMAT_OUTER_NAMESPACE {
 
 namespace Tbc {
 
+    struct TextAttributes {
+        static std::size_t getDefaultWidth() {
 #ifdef TBC_TEXT_FORMAT_CONSOLE_WIDTH
-    const unsigned int consoleWidth = TBC_TEXT_FORMAT_CONSOLE_WIDTH;
+            return TBC_TEXT_FORMAT_CONSOLE_WIDTH;
 #else
-    const unsigned int consoleWidth = 80;
+            static std::size_t width = 0;
+
+            if( !width ) {
+                // Determining the real console width is not trivial as it
+                // needs to be done in different ways for different platforms,
+                // so we rely on the standard environment variable instead.
+                if( char const* const colstr = std::getenv("COLUMNS") ) {
+                    int const colnum = std::atoi(colstr);
+                    if( colnum > 0 )
+                        width = static_cast<std::size_t>(colnum);
+                }
+
+                // Fall back to the hard-coded default.
+                if( !width )
+                    width = 80;
+            }
+
+            return width;
 #endif
+        }
 
-    struct TextAttributes {
         TextAttributes()
         :   initialIndent( std::string::npos ),
             indent( 0 ),
-            width( consoleWidth-1 ),
+            width( getDefaultWidth()-1 ),
             tabChar( '\t' )
         {}
 

srcs/clara.h

@@ -50,12 +50,6 @@ namespace Clara {
 
     namespace Detail {
 
-#ifdef CLARA_CONSOLE_WIDTH
-    const unsigned int consoleWidth = CLARA_CONFIG_CONSOLE_WIDTH;
-#else
-    const unsigned int consoleWidth = 80;
-#endif
-
         // Use this to try and stop compiler from warning about unreachable code
         inline bool isTrue( bool value ) { return value; }
 
@@ -513,7 +507,10 @@ namespace Clara {
             m_boundProcessName = new Detail::BoundUnaryMethod<C,M>( _unaryMethod );
         }
 
-        void optUsage( std::ostream& os, std::size_t indent = 0, std::size_t width = Detail::consoleWidth ) const {
+        void optUsage( std::ostream& os, std::size_t indent = 0, std::size_t width = 0 ) const {
+            if( !width )
+                width = Detail::TextAttributes::getDefaultWidth();
+
             typename std::vector<Arg>::const_iterator itBegin = m_options.begin(), itEnd = m_options.end(), it;
             std::size_t maxWidth = 0;
             for( it = itBegin; it != itEnd; ++it )

srcs/tbc_text_format.h

@@ -11,6 +11,7 @@
 #define TBC_TEXT_FORMAT_H_INCLUDED
 #endif
 
+#include <cstdlib>
 #include <string>
 #include <vector>
 #include <sstream>
@@ -23,17 +24,36 @@ namespace STITCH_TBC_TEXT_FORMAT_OUTER_NAMESPACE {
 
 namespace Tbc {
 
+    struct TextAttributes {
+        static std::size_t getDefaultWidth() {
 #ifdef TBC_TEXT_FORMAT_CONSOLE_WIDTH
-    const unsigned int consoleWidth = TBC_TEXT_FORMAT_CONSOLE_WIDTH;
+            return TBC_TEXT_FORMAT_CONSOLE_WIDTH;
 #else
-    const unsigned int consoleWidth = 80;
+            static std::size_t width = 0;
+
+            if( !width ) {
+                // Determining the real console width is not trivial as it
+                // needs to be done in different ways for different platforms,
+                // so we rely on the standard environment variable instead.
+                if( char const* const colstr = std::getenv("COLUMNS") ) {
+                    int const colnum = std::atoi(colstr);
+                    if( colnum > 0 )
+                        width = static_cast<std::size_t>(colnum);
+                }
+
+                // Fall back to the hard-coded default.
+                if( !width )
+                    width = 80;
+            }
+
+            return width;
 #endif
+        }
 
-    struct TextAttributes {
         TextAttributes()
         :   initialIndent( std::string::npos ),
             indent( 0 ),
-            width( consoleWidth-1 ),
+            width( getDefaultWidth()-1 ),
             tabChar( '\t' )
         {}