MEX compilation error - c++

Question

I'trying to compile the c code with mex for MATLAB 2013a 64 under win7 64
http://www.cs.cornell.edu/People/tj/svm%5Flight/svm_perf.html
According to info from this site the SVMPerf MATLAB interface was done by O Luaces
but only for Linux and MACos and it don't compile under windows
http://www.aic.uniovi.es/~oluaces/Oscars_Home_Page/Personal.html
for this i installed gnumex to have access to gcc for MATLAB and this is ok.
then I compiled with mex and created object files for all involved c programs according
to make file from SVMPerf.
I also compiled mex_interface.cpp file which was used for MATLAB interface under LINUX.
However when I try to link all files I'm getting following error related to my_malloc
svm_learn_main.obj:svm_learn_main.c:(.text+0x470): first defined here
svm_struct_main.obj:svm_struct_main.c:(.text.startup+0x0): multiple definition of
`main'
svm_learn_main.obj:svm_learn_main.c:(.text.startup+0x0): first defined here
Cannot export mexFunction: symbol not defined
mex_interface.obj:mex_interface.cpp:(.text+0x94): undefined reference to
`my_malloc(unsigned long long)'
mex_interface.obj:mex_interface.cpp:(.text+0x218): undefined reference to
`my_malloc(unsigned long long)'
C:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/4.9.0/../../../../x86_64-w64-mingw32
/bin/ld.exe: mex_interface.obj: bad reloc address 0x0 in section `.pdata'
collect2.exe: error: ld returned 1 exit status
link command: gcc -shared C:\Users\KRZYSZ~1\AppData\Roaming\MATHWO~1\MATLAB\R2013a
\gnumex\mex.def -o svm_perf_classify.mexw64 -LC:\Users\KRZYSZ~1\AppData\Roaming
\MATHWO~1\MATLAB\R2013a\gnumex -s mex_interface.obj my_malloc.obj svm_learn_main.obj
svm_learn.obj svm_common.obj svm_hideo.obj svm_struct_learn.obj
svm_struct_classify.obj svm_struct_common.obj svm_struct_main.obj svm_struct_api.obj
svm_struct_classify.obj svm_struct_common.obj svm_struct_main.obj -llibmx -llibmex
-llibmat
I believe it points to this code. my_malloc compiles OK. Any idea ??
void create_argc_argv(const mxArray *options,int *argc,char **argv[]) {
// convert the matlab string of options into a CLI-like input (argc and argv)
*argc=1;
mwSize buflen = mxGetN(options)*sizeof(mxChar)+1;
char *buf = mxMalloc(buflen);
// Copy the string data into buf
mxGetString(options, buf, buflen);
// and separate in argv[]
char **ap, **argv_ptr=(char **)my_malloc(MAX_ARGVS*sizeof(char *));
argv_ptr[0]="OLR";
for (ap = (argv_ptr+1); (*ap = strsep(&buf, " \t")) != NULL;)
if (**ap != '\0') {
(*argc)++;
if (++ap >= &argv_ptr[MAX_ARGVS])
break;
}
// 'buf' shouldn't be freed, since it is converted to the different 'argv[i]'
// by setting to '\0' the tabs and white spaces between options
// (this trick was taken from the 'strsep' man page)
// so, we don't make mxFree(buf);
*argv=argv_ptr;
}
my mex command looks like this
mex -largeArrayDims -DWIN -output svm_perf_classify mex_interface.cpp
svm_learn_main.obj svm_learn.obj svm_common.obj svm_hideo.obj svm_struct_learn.obj
svm_struct_classify.obj svm_struct_common.obj svm_struct_main.obj svm_struct_api.obj
svm_struct_classify.obj svm_struct_common.obj svm_struct_main.obj

Answer 1

It looks like the issue you have isn't MEX related, as the main function is declared more than once. Which makes it hard for the compiler to know where to start running the code. If you have public functions you want to use in svm_learn_main or svm_struct_main, you'll want to separate those from the files containing the main function.

Answer 2

mex -largeArrayDims -DWIN -output svm_perf_classify mex_interface.cpp
svm_perf_classify does not have a source file extension(.c or .cpp or other), so it's considered a executable by compiler.