Merge pull request DrTimothyAldenDavis#726 from mmuetzel/suitesparse_config

SuiteSparse_config: Check if linking to librt is necessary

Author: DrTimothyAldenDavis

SuiteSparse_config/CMakeLists.txt

@@ -103,6 +103,28 @@ if ( SUITESPARSE_USE_STRICT AND SUITESPARSE_CONFIG_USE_OPENMP AND NOT SUITESPARS
     message ( FATAL_ERROR "OpenMP required for SuiteSparse_config but not found" )
 endif ( )
 
+# check for librt in case of fallback to "clock_gettime"
+include ( CheckSymbolExists )
+check_symbol_exists ( clock_gettime "time.h" NO_RT )
+if ( NO_RT )
+    message ( STATUS "Using clock_gettime without librt" )
+    set ( SUITESPARSE_HAVE_CLOCK_GETTIME ON )
+else ( )
+    # check if we need to link to librt for that function
+    set ( _orig_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES} )
+    list ( APPEND CMAKE_REQUIRED_LIBRARIES "rt" )
+    check_symbol_exists ( clock_gettime "time.h" WITH_RT )
+    set ( CMAKE_REQUIRED_LIBRARIES ${_orig_CMAKE_REQUIRED_LIBRARIES} )
+    if ( WITH_RT )
+        message ( STATUS "Using clock_gettime with librt" )
+        set ( SUITESPARSE_HAVE_CLOCK_GETTIME ON )
+    endif ( )
+endif ( )
+
+if ( NOT SUITESPARSE_CONFIG_USE_OPENMP AND NOT SUITESPARSE_HAVE_CLOCK_GETTIME )
+    message ( STATUS "No OpenMP and no clock_gettime available. Timing functions won't work." )
+endif ( )
+
 #-------------------------------------------------------------------------------
 # find the BLAS
 #-------------------------------------------------------------------------------
@@ -208,6 +230,17 @@ if ( SUITESPARSE_CONFIG_USE_OPENMP )
             "$<TARGET_PROPERTY:OpenMP::OpenMP_C,INTERFACE_INCLUDE_DIRECTORIES>" )
         list ( APPEND SUITESPARSE_CONFIG_STATIC_LIBS ${OpenMP_C_LIBRARIES} )
     endif ( )
+else ( )
+    # librt
+    if ( WITH_RT )
+        if ( BUILD_SHARED_LIBS )
+            target_link_libraries ( SuiteSparseConfig PRIVATE "rt" )
+        endif ( )
+        if ( BUILD_STATIC_LIBS )
+            target_link_libraries ( SuiteSparseConfig_static PRIVATE "rt" )
+            list ( APPEND SUITESPARSE_CONFIG_STATIC_LIBS "rt" )
+        endif ( )
+    endif ( )
 endif ( )
 
 # BLAS:

SuiteSparse_config/Config/SuiteSparse_config.h.in

@@ -372,14 +372,13 @@ int SuiteSparse_divcomplex
     // but other packages can themselves use OpenMP.  In this case,
     // those packages should use omp_get_wtime() directly.  This can
     // be done via the SUITESPARSE_TIME macro, defined below:
+    #cmakedefine SUITESPARSE_HAVE_CLOCK_GETTIME
     #if defined ( _OPENMP )
         #define SUITESPARSE_TIMER_ENABLED
         #define SUITESPARSE_TIME (omp_get_wtime ( ))
-    #elif defined ( _POSIX_C_SOURCE )
-        #if _POSIX_C_SOURCE >= 199309L
+    #elif defined ( SUITESPARSE_HAVE_CLOCK_GETTIME )
         #define SUITESPARSE_TIMER_ENABLED
         #define SUITESPARSE_TIME (SuiteSparse_time ( ))
-        #endif
     #else
         // No timer is available
         #define SUITESPARSE_TIME (0)

SuiteSparse_config/SuiteSparse_config.c

@@ -495,7 +495,7 @@ void *SuiteSparse_free      /* always returns NULL */
         tic [1] = 0 ;
     }
 
-#else 
+#else
 
     /* ---------------------------------------------------------------------- */
     /* POSIX timer */
@@ -616,7 +616,7 @@ double SuiteSparse_hypot (double x, double y)
             r = x / y ;
             s = y * sqrt (1.0 + r*r) ;
         }
-    } 
+    }
     return (s) ;
 }
 

SuiteSparse_config/SuiteSparse_config.h

@@ -372,14 +372,13 @@ int SuiteSparse_divcomplex
     // but other packages can themselves use OpenMP.  In this case,
     // those packages should use omp_get_wtime() directly.  This can
     // be done via the SUITESPARSE_TIME macro, defined below:
+    #define SUITESPARSE_HAVE_CLOCK_GETTIME
     #if defined ( _OPENMP )
         #define SUITESPARSE_TIMER_ENABLED
         #define SUITESPARSE_TIME (omp_get_wtime ( ))
-    #elif defined ( _POSIX_C_SOURCE )
-        #if _POSIX_C_SOURCE >= 199309L
+    #elif defined ( SUITESPARSE_HAVE_CLOCK_GETTIME )
         #define SUITESPARSE_TIMER_ENABLED
         #define SUITESPARSE_TIME (SuiteSparse_time ( ))
-        #endif
     #else
         // No timer is available
         #define SUITESPARSE_TIME (0)