[INSTALL] Added a section "If 'gmp.h' and 'libgmp' do not match".

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@7279 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 100 insertions, 1 deletions

diff --git a/INSTALL b/INSTALL
index 5a824843d..d4b08e602 100644
--- a/INSTALL
+++ b/INSTALL
@@ -170,7 +170,7 @@ specific architecture.
                         *after* the ones that are currently declared,
                         so that DIR will have a lower precedence. Also,
                         this may not work if DIR is a system directory
-                        (typically /usr or /usr/local).
+                        (typically /usr or /usr/local); see below.
 
 --with-gmp-build=DIR    assumes that DIR contains the GMP build directory,
                         and enables the use of GMP internals (see above).
@@ -206,6 +206,105 @@ CC/CFLAGS as explained below.
 Run "./configure --help" to see the other options (autoconf default options).
 
 
+If 'gmp.h' and 'libgmp' do not match
+====================================
+
+Under some circumstances, the configure script may output a message
+saying:
+
+  'gmp.h' and 'libgmp' seem to have different versions or
+  we cannot run a program linked with GMP (if you cannot
+  see the version numbers above). [...]
+
+Even though the configure script does not fail in such a case, this
+message most often indicates a real error, which needs to be avoided.
+Possible causes are:
+
+* The wanted GMP library does not have the same ABI as the one chosen
+  to build MPFR. The consequences may be:
+
+    - A different GMP library (with the correct ABI) has been found,
+      but does not have the same version as 'gmp.h'.
+
+    - No other GMP libraries have been found (in this case, no version
+      numbers should be printed above the warning message).
+
+  This is incorrect and one of the following steps (make, make check)
+  will probably fail. GMP (actually gmp.h) now provides CC and CFLAGS
+  information to select the correct ABI, so that this problem should
+  no longer occur; but if GMP was provided by a binary package, such
+  information may not be valid. See the
+
+    checking for CC and CFLAGS in gmp.h...
+
+  line in the configure output (about the 11th line) and the following
+  few ones for more information. You may need to reinstall GMP or to
+  provide your own CC and/or CFLAGS. See also the remaining of this
+  INSTALL file.
+
+* A configure option like --with-gmp or --with-gmp-include was used
+  with a system include directory, e.g. one of the following:
+
+    --with-gmp=/usr
+    --with-gmp=/usr/local
+    --with-gmp-include=/usr/include
+    --with-gmp-include=/usr/local/include
+
+  GCC (and possibly other compilers) will ignore such a directive for
+  include directories (but this rule is not applied for the library
+  itself!). This means that the library search paths will be reordered
+  as declared, but the specified include directory will still be near
+  the end of the include search paths (thus with a low precedence).
+  This is not a problem if only one GMP version is installed, but
+  otherwise, a wrong gmp.h may be chosen, so that the versions of
+  gmp.h and libgmp may not match. The suggestions are the following:
+
+    - If you want to use the GMP version under /usr, then you should
+      uninstall all the other GMP versions (header and library files)
+      that may be seen in the search paths, in particular those under
+      /usr/local.
+
+    - If you want to use the GMP version under /usr/local, then you
+      should uninstall all the other GMP versions (header and library
+      files) that may be seen in the search paths, but *NOT* the one
+      under /usr (the version under /usr is provided by the OS vendor,
+      and changing/removing anything related to it may break your
+      system, and /usr should have a lower precedence than /usr/local
+      anyway).
+
+  To find where GMP versions have been installed:
+
+    $ locate libgmp  (if you have a locate database)
+
+  and if the compiler is GCC:
+
+    $ gcc -print-file-name=libgmp.so     (under most systems)
+    $ gcc -print-file-name=libgmp.dylib  (under Mac OS X)
+
+  and if this does not work, you may try:
+
+    $ gcc -print-search-dirs
+
+* An official GCC version was used under Debian GNU/Linux. Problems
+  may come from the fact that Debian chose a different convention
+  for library search paths concerning 32-bit and 64-bit libraries.
+  A possible problem can be, for instance:
+
+  [Debian's GCC, correct library path]
+  $ gcc -print-file-name=libgmp.so
+  /home/vlefevre/gmp/athlon64/lib/../lib/libgmp.so
+
+  [Official GCC, incorrect library path]
+  $ gcc-4.3.1 -print-file-name=libgmp.so
+  /usr/lib/../lib64/libgmp.so
+
+  The solution: use a GCC provided by Debian or add symbolic links
+  such as lib64 -> lib (on 64-bit machines) for your library paths.
+
+* The problem may also be temporary and only due to the fact that
+  libtool could not be used at this time. This is unlikely, though.
+
+
 In case of problem
 ==================