Suppose
  sub1.f90  contains subroutine  sub1
  sub45.f90 contains subroutines sub4 and sub5

% ar -r libsubs.a sub1.o sub45.o
% ar -t libsubs.a
sub1.o
sub45.o

% nm libsubs.a

sub1.o:
         U _g95_filename
         U _g95_get_ioparm
         U _g95_ioparm
         U _g95_line
         U _g95_st_write
         U _g95_st_write_done
         U _g95_transfer_character
00000000 T sub1_

sub45.o:
         U _g95_filename
         U _g95_get_ioparm
         U _g95_ioparm
         U _g95_line
         U _g95_st_write
         U _g95_st_write_done
         U _g95_transfer_character
         U sub2_
00000000 T sub4_
00000078 T sub5_

  "T" The symbol is in the text (code) section.
  "U" The symbol is undefined.

Can write  nm sub1.o  as well.

However:
% strip sub1.o
% nm sub1.o
nm: sub1.o: no symbols
--------------------------------------------------
typedef struct {
  double v[10];
  int n;
} my_mxArray;

// void ex1(my_mxArray const * s[])  or
void ex1(const my_mxArray * s[])  // Like the MEX-file
{
  (*s[0]).v[5] = 7;  // illegal
  s[0]->v[5] = 7;    // illegal
  s[1] = s[0];       // OK
}

void ex2(my_mxArray * const s[])
{
  s[0]->v[5] = 7;    // OK
  s[1] = s[0];       // illegal
}

void ex3(const my_mxArray * const s[])
{
  s[0]->v[5] = 7;    // illegal
  s[1] = s[0];       // illegal
}

void ex4(const my_mxArray * const s[])
{
  double *pv;

  pv = (double *) s[0]->v;
  pv[5] = 7;         // OK
}