[mercury-users] Problem with shared libraries with Mercury 0.13.1 on Mac OS X 10.4.11

[Markus Morawitz]

Hello,

I was able to install Mercury 0.13.1 on Mac OS X 10.4.11 running gcc  
3.3 without any problem.
Also most of the tests in mercury-tests-0.13.1 succeeded.

Now I am trying to install and use some of the provided libraries in  
mercury-extras-0.13.1.
Especially I looked at the complex_numbers library.

There I noticed a general problem with installing shared libraries on  
Mac.

Although the variable INSTALL_PREFIX is correctly set in the Mmakefile
to <base-mercury-path>/extras and the command mmake install also copies
the resulting files (including the shared library) to the correct  
place under
<base-mercury-path>/extras.

But the library itself is linked with a false install-name. The path  
within install-name
is constructed independent of the setting in INSTALL_PREFIX only on  
<base-mercury-path>.
The consequence is that the resulting executables (which can be  
linked correctly) are not able to
run because dyld is searching the library in a false path.

Further investigation has revealed that the the generated dependency  
file (with mmake depend) *.dep
is the main source of this error. There the rules for generating and  
linking the shared library uses the
parameter -install-name with a path independent of the settings of  
INSTALL_PREFIX in the Mmakefile
always pointing to the base mercury installation.

The general problem seems to be that the command "mmc --generate- 
dependencies command"
responsible to produce the *.dep file is not aware of the setting of  
the variable INSTALL_PREFIX.
But the part responsible to install (copy) the library to the right  
place (rules in Mmake.rules) works
fine because INSTALL_PREFIX is used.
Also the making and linking of an executable linked to the library  
works fine using the variables
EXTRA_LIB_DIRS and EXTRA_LIBRARIES.
Only the execution itself invoking dyld fails again.

I also found a workaround.

I changed the definition of the variable MCD within Mmake.vars:

original definition of MCD in Mmake.vars:
MCD		= $(MC) --generate-dependencies

my definition of MCD in Mmake.vars:
MCD		= $(MC) --generate-dependencies --install-prefix $(INSTALL_PREFIX)

With this definition the *.dep files are generated correctly using  
the settings of INSTALL_PREFIX in the Mmakefile.
The install-name of the library then is according to the place where  
the libraries get copied by the install target.
And dyld can find the libraries.

Best regards



Markus Morawitz
markusmorawitz at gmx.de


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