Thank you Steve for your help,
I tried adding the LINK_FLAGS you suggested but I got the same errors.
Here I attach the whole Makefile:
F77 = gfortran
FLAGS = -c -O3
CXX = c++
MLINKDIR = /usr/local/Wolfram/Mathematica/9.0/SystemFiles/Links/MathLink/DeveloperKit/Linux-x86-64/CompilerAdditions
LINK_FLAGS = -lML64i3 -lgfortran -lrt -lpthread -lm
OBJS = fpdf.o CT12Pdf.o
pdf : $(OBJS) pdf.c
$(CXX) -o $@ -I$(MLINKDIR) -L$(MLINKDIR) $(LINK_FLAGS) $(OBJS) pdf.c
pdf.c : pdf.tm
./mprep $? -o $@
.f.o: ; $(F77) $(FLAGS) $*.f
clean :
$(RM) $(OBJS) pdf.c
I think the other lines works properly because I can get the output files "fpdf.o", "CT12Pdf.o" and "pdf.c"
Here I attach the full list of errors I get when launching the "make" command
gfortran -c -O3 fpdf.f
gfortran -c -O3 CT12Pdf.f
./mprep pdf.tm -o pdf.c
c++ -o pdf -I/usr/local/Wolfram/Mathematica/9.0/SystemFiles/Links/MathLink/DeveloperKit/Linux-x86-64/CompilerAdditions -L/usr/local/Wolfram/Mathematica/9.0/SystemFiles/Links/MathLink/DeveloperKit/Linux-x86-64/CompilerAdditions -lML64i3 -lrt -lpthread -lm -lgfortran fpdf.o CT12Pdf.o pdf.c
CT12Pdf.o: In function `readpds0_':
CT12Pdf.f:(.text+0x21b): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x232): undefined reference to `_gfortran_transfer_character'
CT12Pdf.f:(.text+0x23f): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x28f): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x2a6): undefined reference to `_gfortran_transfer_character'
CT12Pdf.f:(.text+0x2b3): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x2cc): undefined reference to `_gfortran_compare_string'
CT12Pdf.f:(.text+0x31c): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x333): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x34a): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x361): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x378): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x38d): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x3b1): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x412): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x429): undefined reference to `_gfortran_transfer_character'
CT12Pdf.f:(.text+0x436): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x44f): undefined reference to `_gfortran_compare_string'
CT12Pdf.f:(.text+0x49f): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x4b6): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x4cd): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x4e2): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x4f7): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x50c): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x523): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x53a): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x547): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x5a4): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x5bb): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x5d2): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x5e9): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x5fe): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x627): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x699): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x6b0): undefined reference to `_gfortran_transfer_character'
CT12Pdf.f:(.text+0x6bd): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x6f6): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x70d): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x724): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x73b): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0x752): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x769): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x77e): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x78b): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x7db): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x7f2): undefined reference to `_gfortran_transfer_character'
CT12Pdf.f:(.text+0x7ff): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x838): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x84f): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x866): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x87b): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x892): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x8a7): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0x8b4): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x91b): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x943): undefined reference to `_gfortran_transfer_character'
CT12Pdf.f:(.text+0x95a): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0x9aa): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0x9c1): undefined reference to `_gfortran_transfer_character'
CT12Pdf.f:(.text+0x9ce): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0xa14): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0xa2b): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xa42): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xa83): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xa9c): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xab5): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xad1): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0xbb5): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0xbcc): undefined reference to `_gfortran_transfer_character'
CT12Pdf.f:(.text+0xbd9): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0xc12): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0xc29): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xc40): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xc7a): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xc91): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0xd16): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0xd2d): undefined reference to `_gfortran_transfer_character'
CT12Pdf.f:(.text+0xd3a): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0xd88): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0xdc2): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xdd9): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0xe19): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0xe30): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xe47): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xe8f): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xea8): undefined reference to `_gfortran_transfer_real'
CT12Pdf.f:(.text+0xefa): undefined reference to `_gfortran_st_read'
CT12Pdf.f:(.text+0xf0f): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0xf24): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0xf39): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0xf50): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0xf67): undefined reference to `_gfortran_transfer_integer'
CT12Pdf.f:(.text+0xf74): undefined reference to `_gfortran_st_read_done'
CT12Pdf.f:(.text+0xfb3): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0xfca): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0xfd7): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x1011): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x1028): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x103f): undefined reference to `_gfortran_transfer_real_write'
CT12Pdf.f:(.text+0x1056): undefined reference to `_gfortran_transfer_real_write'
CT12Pdf.f:(.text+0x1063): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x106c): undefined reference to `_gfortran_stop_string'
CT12Pdf.o: In function `nextun_':
CT12Pdf.f:(.text+0x10b3): undefined reference to `_gfortran_st_inquire'
CT12Pdf.f:(.text+0x10d4): undefined reference to `_gfortran_stop_string'
CT12Pdf.o: In function `partonx12_':
CT12Pdf.f:(.text+0x1b87): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x1b9b): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x1baf): undefined reference to `_gfortran_transfer_real_write'
CT12Pdf.f:(.text+0x1bb9): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x1bc2): undefined reference to `_gfortran_stop_string'
CT12Pdf.f:(.text+0x1c01): undefined reference to `_gfortran_st_write'
CT12Pdf.o: In function `ct12pdf_':
CT12Pdf.f:(.text+0x1c7a): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x1c8e): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x1ca0): undefined reference to `_gfortran_transfer_real_write'
CT12Pdf.f:(.text+0x1caa): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x1d34): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x1d48): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x1d52): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x1d7d): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x1d91): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x1da3): undefined reference to `_gfortran_transfer_integer_write'
CT12Pdf.f:(.text+0x1db7): undefined reference to `_gfortran_transfer_integer_write'
CT12Pdf.f:(.text+0x1dc1): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x1df4): undefined reference to `_gfortran_stop_string'
CT12Pdf.f:(.text+0x1e1f): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x1e33): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x1e45): undefined reference to `_gfortran_transfer_real_write'
CT12Pdf.f:(.text+0x1e4f): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x1e58): undefined reference to `_gfortran_stop_string'
CT12Pdf.o: In function `setct12_':
CT12Pdf.f:(.text+0x1eaf): undefined reference to `_gfortran_st_inquire'
CT12Pdf.f:(.text+0x1f01): undefined reference to `_gfortran_st_open'
CT12Pdf.f:(.text+0x1f44): undefined reference to `_gfortran_st_close'
CT12Pdf.f:(.text+0x1f71): undefined reference to `_gfortran_stop_string'
CT12Pdf.f:(.text+0x1f9c): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x1fb0): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x1fc2): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x1fd6): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x1fe0): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x1fe9): undefined reference to `_gfortran_stop_string'
CT12Pdf.o: In function `ct12alphas_':
CT12Pdf.f:(.text+0x215a): undefined reference to `_gfortran_stop_string'
CT12Pdf.f:(.text+0x2182): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x218a): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x21b2): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x21c4): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x21cc): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x21f4): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x2206): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x220e): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x2236): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x2248): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x2250): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x2278): undefined reference to `_gfortran_st_write'
CT12Pdf.f:(.text+0x228a): undefined reference to `_gfortran_transfer_character_write'
CT12Pdf.f:(.text+0x2292): undefined reference to `_gfortran_st_write_done'
CT12Pdf.f:(.text+0x229b): undefined reference to `_gfortran_stop_string'
CT12Pdf.o: In function `ct12mass_':
CT12Pdf.f:(.text+0x22c2): undefined reference to `_gfortran_stop_string'
/tmp/ccaI54W2.o: In function `_tr0(MLink*)':
pdf.c:(.text+0x84): undefined reference to `MLGetInteger'
pdf.c:(.text+0xa5): undefined reference to `MLGetReal'
pdf.c:(.text+0xc6): undefined reference to `MLGetReal'
pdf.c:(.text+0xe0): undefined reference to `MLNewPacket'
pdf.c:(.text+0x13c): undefined reference to `MLPutFunction'
pdf.c:(.text+0x157): undefined reference to `MLPutReal'
/tmp/ccaI54W2.o: In function `MLInstall':
pdf.c:(.text+0x181): undefined reference to `MLConnect'
pdf.c:(.text+0x1bf): undefined reference to `MLPutSymbol'
pdf.c:(.text+0x1d4): undefined reference to `MLFlush'
/tmp/ccaI54W2.o: In function `_definepattern(MLink*, char*, char*, int)':
pdf.c:(.text+0x22d): undefined reference to `MLPutFunction'
pdf.c:(.text+0x240): undefined reference to `MLPutString'
pdf.c:(.text+0x253): undefined reference to `MLPutString'
pdf.c:(.text+0x264): undefined reference to `MLPutInteger'
pdf.c:(.text+0x270): undefined reference to `MLError'
/tmp/ccaI54W2.o: In function `_MLDoCallPacket(MLink*, func*, int)':
pdf.c:(.text+0x2a7): undefined reference to `MLGetInteger'
pdf.c:(.text+0x30f): undefined reference to `MLCheckFunction'
pdf.c:(.text+0x390): undefined reference to `MLClearError'
pdf.c:(.text+0x3a5): undefined reference to `MLPutSymbol'
pdf.c:(.text+0x3cd): undefined reference to `MLEndPacket'
pdf.c:(.text+0x3dd): undefined reference to `MLNewPacket'
/tmp/ccaI54W2.o: In function `MLAnswer':
pdf.c:(.text+0x44d): undefined reference to `MLError'
pdf.c:(.text+0x45d): undefined reference to `MLNextPacket'
/tmp/ccaI54W2.o: In function `refuse_to_be_a_frontend(MLink*)':
pdf.c:(.text+0x4ad): undefined reference to `MLPutFunction'
pdf.c:(.text+0x4c3): undefined reference to `MLPutFunction'
pdf.c:(.text+0x4d9): undefined reference to `MLPutFunction'
pdf.c:(.text+0x4ef): undefined reference to `MLPutFunction'
pdf.c:(.text+0x500): undefined reference to `MLPutSymbol'
pdf.c:(.text+0x511): undefined reference to `MLPutSymbol'
pdf.c:(.text+0x527): undefined reference to `MLPutFunction'
pdf.c:(.text+0x53d): undefined reference to `MLPutFunction'
pdf.c:(.text+0x54e): undefined reference to `MLPutSymbol'
pdf.c:(.text+0x561): undefined reference to `MLTransferExpression'
pdf.c:(.text+0x577): undefined reference to `MLPutFunction'
pdf.c:(.text+0x58d): undefined reference to `MLPutFunction'
pdf.c:(.text+0x59e): undefined reference to `MLPutSymbol'
pdf.c:(.text+0x5af): undefined reference to `MLPutString'
pdf.c:(.text+0x5c0): undefined reference to `MLPutSymbol'
pdf.c:(.text+0x5d1): undefined reference to `MLPutSymbol'
pdf.c:(.text+0x5dd): undefined reference to `MLEndPacket'
pdf.c:(.text+0x5eb): undefined reference to `MLNewPacket'
pdf.c:(.text+0x5f7): undefined reference to `MLNextPacket'
pdf.c:(.text+0x622): undefined reference to `MLNewPacket'
pdf.c:(.text+0x62e): undefined reference to `MLError'
/tmp/ccaI54W2.o: In function `MLEvaluate':
pdf.c:(.text+0x66f): undefined reference to `MLPutFunction'
pdf.c:(.text+0x689): undefined reference to `MLPutFunction'
pdf.c:(.text+0x6a0): undefined reference to `MLPutString'
pdf.c:(.text+0x6b0): undefined reference to `MLEndPacket'
/tmp/ccaI54W2.o: In function `MLEvaluateString':
pdf.c:(.text+0x710): undefined reference to `MLNewPacket'
pdf.c:(.text+0x747): undefined reference to `MLNewPacket'
pdf.c:(.text+0x753): undefined reference to `MLError'
/tmp/ccaI54W2.o: In function `_MLMain(char**, char**, char*)':
pdf.c:(.text+0x7c1): undefined reference to `MLInitialize'
pdf.c:(.text+0x811): undefined reference to `MLOpenString'
pdf.c:(.text+0x83e): undefined reference to `MLOpenArgcArgv'
pdf.c:(.text+0x861): undefined reference to `MLErrorString'
pdf.c:(.text+0x876): undefined reference to `MLAlert'
pdf.c:(.text+0x89d): undefined reference to `MLSetYieldFunction'
pdf.c:(.text+0x8bf): undefined reference to `MLSetMessageHandler'
pdf.c:(.text+0x910): undefined reference to `MLClose'
pdf.c:(.text+0x91f): undefined reference to `MLDeinitialize'
collect2: error: ld returned 1 exit status
make: *** [pdf] Error 1
