Disabled all bindings to FFTW because FFTW isn't threadsafe.

dlib/CMakeLists.txt

@@ -72,8 +72,7 @@ if (NOT TARGET dlib)
    "Disable this if you don't want to link against libjpeg" )
    set (DLIB_LINK_WITH_SQLITE3_STR
    "Disable this if you don't want to link against sqlite3" )
-   set (DLIB_LINK_WITH_FFTW_STR
-   "Disable this if you don't want to link against fftw" )
+   #set (DLIB_LINK_WITH_FFTW_STR "Disable this if you don't want to link against fftw" )
 
    option(DLIB_ISO_CPP_ONLY ${DLIB_ISO_CPP_ONLY_STR} OFF)
    option(DLIB_NO_GUI_SUPPORT ${DLIB_NO_GUI_SUPPORT_STR} OFF)
@@ -84,7 +83,7 @@ if (NOT TARGET dlib)
    option(DLIB_LINK_WITH_LIBPNG ${DLIB_LINK_WITH_LIBPNG_STR} ON)
    option(DLIB_LINK_WITH_LIBJPEG ${DLIB_LINK_WITH_LIBJPEG_STR} ON)
    option(DLIB_LINK_WITH_SQLITE3 ${DLIB_LINK_WITH_SQLITE3_STR} ON)
-   option(DLIB_LINK_WITH_FFTW ${DLIB_LINK_WITH_FFTW_STR} ON)
+   #option(DLIB_LINK_WITH_FFTW ${DLIB_LINK_WITH_FFTW_STR} ON)
 
    set(source_files 
          base64/base64_kernel_1.cpp

dlib/matrix/matrix_fft.h

@@ -8,9 +8,13 @@
 #include "../hash.h"
 #include "../algs.h"
 
+
+// No using FFTW until it becomes thread safe!
+#if 0
 #ifdef DLIB_USE_FFTW
 #include <fftw3.h>
 #endif // DLIB_USE_FFTW
+#endif
 
 namespace dlib
 {
@@ -513,6 +517,15 @@ namespace dlib
 
 // ----------------------------------------------------------------------------------------
 
+    /*
+        I'm disabling any use of the FFTW bindings because FFTW is, as of this writing, not
+        threadsafe as a library.  This means that if multiple threads were to make
+        concurrent calls to these fft routines then the program could crash.  If at some
+        point FFTW is fixed I'll turn these bindings back on.
+
+        See https://github.com/FFTW/fftw3/issues/16
+    */
+#if 0
 #ifdef DLIB_USE_FFTW
 
     template <long NR, long NC, typename MM, typename L>
@@ -597,6 +610,7 @@ namespace dlib
     inline void ifft_inplace(matrix<std::complex<double> >& data) {data = call_fftw_ifft(data);}
 
 #endif // DLIB_USE_FFTW
+#endif // end of #if 0
 
 // ----------------------------------------------------------------------------------------
 

dlib/matrix/matrix_fft_abstract.h

@@ -40,10 +40,6 @@ namespace dlib
                 - starting with D(0,0), D contains progressively higher frequency components
                   of the input data.
                 - ifft(D) == D
-            - if DLIB_USE_FFTW is #defined then this function will use the very fast fftw
-              library when given matrix<double> objects instead of dlib's default fft
-              implementation.  Note that you must also link to the fftw3 library to use
-              this feature.
     !*/
 
 // ----------------------------------------------------------------------------------------
@@ -64,10 +60,6 @@ namespace dlib
                 - D.nr() == data.nr()
                 - D.nc() == data.nc()
                 - fft(D) == data 
-            - if DLIB_USE_FFTW is #defined then this function will use the very fast fftw
-              library when given matrix<double> objects instead of dlib's default fft
-              implementation.  Note that you must also link to the fftw3 library to use
-              this feature.
     !*/
 
 // ----------------------------------------------------------------------------------------
@@ -91,10 +83,6 @@ namespace dlib
             - This function is identical to fft() except that it does the FFT in-place.
               That is, after this function executes we will have:
                 - #data == fft(data)
-            - if DLIB_USE_FFTW is #defined then this function will use the very fast fftw
-              library when given double precision matrices instead of dlib's default fft
-              implementation.  Note that you must also link to the fftw3 library to use
-              this feature.
     !*/
 
 // ----------------------------------------------------------------------------------------
@@ -120,10 +108,6 @@ namespace dlib
                 - #data == ifft(data)*data.size()
                 - Note that the output needs to be divided by data.size() to complete the 
                   inverse transformation.  
-            - if DLIB_USE_FFTW is #defined then this function will use the very fast fftw
-              library when given double precision matrices instead of dlib's default fft
-              implementation.  Note that you must also link to the fftw3 library to use
-              this feature.
     !*/
 
 // ----------------------------------------------------------------------------------------