Trouble Linking when compiling a MEX file - c

Question

I am trying to compile a mex file that I wrote in order to run a pre-existing C program in MATLAB. I am getting the following errors:
>> mex src/main.c -Iinclude -I/Users/my_name/mpfr-3.1.1/src/ -I/Users/my_name/gmp-5.0.5 -Lsrc0 -output cpdetect_c
Undefined symbols for architecture x86_64:
"_binomial_main", referenced from:
_cpdetect in main.o
"_gaussian1_main", referenced from:
_cpdetect in main.o
"_gaussianU_main", referenced from:
_cpdetect in main.o
"_mpfr_clears", referenced from:
_cpdetect in main.o
"_mpfr_exp10", referenced from:
_cpdetect in main.o
"_mpfr_inits2", referenced from:
_cpdetect in main.o
"_mpfr_set_d", referenced from:
_cpdetect in main.o
"_poisson_main", referenced from:
_cpdetect in main.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
I am confused because these functions are all part of files that I #Include in my code. How do I get the compiler to find them?
I am running MATLAB R2013a on Mac OS X 10.8 with Xcode version 4.6.3.
Thanks for any advice!
UPDATE1:
#Shai: Contents of my src0 folder:
>> ls src0
Makefile gaussian1.o test_gaussian1.c test_tools.c
Makefile.am loadtraj.c test_gaussian1_point_calc.c test_tools.o
Makefile.in loadtraj.o test_load tools.c
binomial.c main.c test_load.c tools.o
binomial.o main.o test_load.o
cpdetect poisson.c test_poisson.c
gaussian1.c poisson.o test_tools
This C program (originally meant to run on the command line) came from a friend and already had the src0 folder present. I modified the code files in the 'src' folder when writing the mex function, but I didn't touch the src0 folder.
UPDATE 2:
I realized I was pointing to the wrong location for mpfr. I am now using the following compile command:
>> mex src/main.c src/binomial.c src/gaussian1.c src/gaussianU.c src/poisson.c -Iinclude -I/usr/local/include -lmpfr -output cpdetect_c
and it is giving the following errors:
Undefined symbols for architecture x86_64:
"_mpfr_mul_d", referenced from:
_gaussian1_calc_constant_part in gaussian1.o
_gaussianU_calc_constant_part in gaussianU.o
"_mpfr_printf", referenced from:
_find_gaussian1_change_point in gaussian1.o
_gaussian1_point_calc in gaussian1.o
_gaussianU_calc_constant_part in gaussianU.o
_find_gaussianU_change_point in gaussianU.o
_find_poisson_change_point in poisson.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
mex: link of ' "cpdetect_c.mexmaci64"' failed.
This is strange. It's not like the compiler can't find any of the mpfr functions - there are lots of others that it seems to be finding without any trouble (and if I deliberately omit the -lmpfr flag, I get a much longer list of undefined symbols). I did confirm that mpfr_mul_d and mpfr_printf are part of the mpfr distribution I installed. Any ideas? Thanks.

Answer 1

The answer was provided by Amro - it is necessary to both point to the location of the library (using the flag -L/usr/local/lib in this case) and to tell the compiler to link to it (using the flag -lmpfr). Thanks also to Shai for help troubleshooting this.