Compilation with an environment variable SLIC3R_HAS_BROKEN_CROAK set

will force the perl confess / croak called from a C++ code to
print an error message and exit. There is a bug in some Strawberry
Perl instalations leading to an interpreter hang up and an exit
with a reasonable message is better than that.

xs/Build.PL

@@ -42,6 +42,14 @@ if ($ENV{SLIC3R_GUI})
 #    push @early_includes, qw(slic3r/GUI/wxinit.h);
 }
 
+if ($ENV{SLIC3R_HAS_BROKEN_CROAK})
+{
+    # Some Strawberry Perl builds (mainly the latest 64bit builds) have a broken mechanism
+    # for emiting Perl exception after handling a C++ exception. Perl interpreter
+    # simply hangs. Better to show a message box in that case and stop the application.
+    push @cflags, qw(-DSLIC3R_HAS_BROKEN_CROAK)
+}
+
 # search for Boost in a number of places
 my @boost_include = ();
 if (defined $ENV{BOOST_INCLUDEDIR}) {

xs/src/libslic3r/utils.cpp

@@ -1,3 +1,37 @@
+#ifdef SLIC3R_HAS_BROKEN_CROAK
+
+// Some Strawberry Perl builds (mainly the latest 64bit builds) have a broken mechanism
+// for emiting Perl exception after handling a C++ exception. Perl interpreter
+// simply hangs. Better to show a message box in that case and stop the application.
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifdef WIN32
+#include <Windows.h>
+#endif
+
+void confess_at(const char *file, int line, const char *func, const char *format, ...)
+{
+    char dest[1024*8];
+    va_list argptr;
+    va_start(argptr, format);
+    vsprintf(dest, format, argptr);
+    va_end(argptr);
+
+    strcat(dest, "\r\n Closing the application.\r\n");
+    #ifdef WIN32
+    ::MessageBoxA(NULL, dest, "Slic3r Prusa Edition", MB_OK | MB_ICONERROR);
+    #endif;
+
+    // Give up.
+    printf(dest);
+    exit(-1);
+}
+
+#else
+
 #include <xsinit.h>
 
 void
@@ -26,3 +60,5 @@ confess_at(const char *file, int line, const char *func,
      LEAVE;
     #endif
 }
+
+#endif

xs/src/xsinit.h

@@ -153,4 +153,13 @@ SV* polynode2perl(const ClipperLib::PolyNode& node);
 
 }
 
+#ifdef SLIC3R_HAS_BROKEN_CROAK
+#undef croak
+#ifdef _MSC_VER
+    #define croak(...) confess_at(__FILE__, __LINE__, __FUNCTION__, __VA_ARGS__)
+#else
+    #define croak(...) confess_at(__FILE__, __LINE__, __func__, __VA_ARGS__)
+#endif
+#endif
+
 #endif