I have a code that is a mix of Fortran, C and R. it’s a simulation code. The backend/solver is in Fortran and C and R is used as the wrapper for creating simulation workflow and launching the process.
I would like to do some profiling using gprof so what I did is I added the relevant flags to my makefiles. Here is the structure of directories:

Let’s say my code is located in the following path

/home/myusername/DEV/simcode/src

The parent makefile is located in src then I have the following sub-makefiles

src/Global/fortran/Makefile
src/TS/c/Makefile
src/TS/fortran/ReadModelData/Makefile
src/TS/fortran/RunSim/Makefile

So I modified all my sub-makefiles in the following fashion:

FC=gfortran
LD=gfortran
OPT=-O2
DBG=-g
PROF= -pg
ifdef SYSTEMROOT
# Windows OS
    SIM_GLOBAL = libCodeGlobal.dll
    FFLAGS = $(OPT) $(DBG) -cpp -fno-underscoring $(PROF)
    LDFLAGS = $(OPT) $(DBG) $(PROF)
else
    ifeq ($(shell uname),Linux)
# GNU/Linux OS
        SIM_GLOBAL = libCodeGlobal.so
        FFLAGS = $(OPT) $(DBG) -cpp -fPIC -fno-underscoring $(PROF)
        LDFLAGS = $(OPT) $(DBG) $(PROF)
    else
# Mac OSX
        SIM_GLOBAL = libCodeGlobal.dylib
        FFLAGS = $(OPT) $(DBG) -cpp -fno-underscoring $(PROF)
        LDFLAGS = $(OPT) $(DBG) $(PROF)
    endif
endif

I modified all Makefiles in the same manner as they are pretty much the same. The I ran

make clean
make all

In

/home/myusername/DEV/simcode/src

Where my parent Makefile is located. Then I ran

R CMD INSTALL .

This is how I install my code, this installs my code on a path such as

/home/myusername/R/x86_64-pc-linux-gnu-library/4.0/MYCODE

where my *so files are located.

Then simply opened an R session by typing R in terminal and loading my code in it

library(MYCODE)

Then running a simulation test case

source("path to the test case file which is an `R` script")

Based on what I understood this process should create a file called gmon.out which is the could be used to analyze the performance using gprof, but I don’t get the gmon.out file.
I checked the installation of gprof and it is installed, i also ran a simple test case to see if it creates gprof file and it properly did, so the problem should be coming from my Simulation code and probably my makefiles.
Any help would be appreciated. Concerning my operating system I’m working on linux if it helps.