diff --git a/c/README.md b/c/README.md
new file mode 100644
index 0000000..437d146
--- /dev/null
+++ b/c/README.md
@@ -0,0 +1 @@
+This is the C interface for calling the Fortran version of ODRPACK.
\ No newline at end of file
diff --git a/include/odrpack.h b/c/include/ordpack/odrpack.h
similarity index 64%
rename from include/odrpack.h
rename to c/include/ordpack/odrpack.h
index a12ca92..d5fbd15 100644
--- a/include/odrpack.h
+++ b/c/include/ordpack/odrpack.h
@@ -6,13 +6,6 @@
 #define ODRPACK_EXTERN extern
 #endif
 
-typedef void (*minpack_func)(
-    int /* n */,
-    const double * /* x */,
-    double * /* fvec */,
-    int * /* iflag */,
-    void * /* udata */);
-
 /**
  * @brief User-supplied function for evaluating the model, computing predicted values and their Jacobians.
  *
@@ -37,23 +30,43 @@ typedef void (*minpack_func)(
  *                1 - current `beta` and `x+delta` are not acceptable; ODRPACK95 should select values closer to most recently used values if possible,
  *               -1 - current `beta` and `x+delta` are not acceptable; ODRPACK95 should stop.
  */
-typedef void (*odrpack_fcn)(
-    int /* n */,
-    int /* m */,
-    int /* np */,
-    int /* nq */,
-    int /* ldn */,
-    int /* ldm */,
-    int /* ldnp */,
-    const double * /* beta */,
-    const double * /* xplusd */,
-    const int * /* ifixb */,
-    const int * /* ifixx */,
-    int /* ldifx */,
-    int /* ideval */,
-    double * /* f */,
-    double * /* fjacb */,
-    double * /* fjacd */,
-    int * /* istop */
+ODRPACK_EXTERN typedef void (*odrpack_fcn)(
+    int n,
+    int m,
+    int np,
+    int nq,
+    int ldn,
+    int ldm,
+    int ldnp,
+    const double *beta,
+    const double *xplusd,
+    const int *ifixb,
+    const int *ifixx,
+    int ldifx,
+    int ideval,
+    double *f,
+    double *fjacb,
+    double *fjacd,
+    int *istop);
 
-);
\ No newline at end of file
+/**
+ * @brief Wrapper for the ODR routine including only mandatory arguments.
+ *
+ * @param fcn  User-supplied subroutine for evaluating the model.
+ * @param n    Number of observations.
+ * @param m    Number of columns of data in the independent variable.
+ * @param np   Number of function parameters.
+ * @param nq   Number of responses per observation.
+ * @param beta Function parameters. Array of size np.
+ * @param y    Dependent variable. Unused when the model is implicit. 2D array of size n x nq.
+ * @param x    Explanatory variable. 2D array of size n x m.
+ */
+ODRPACK_EXTERN void odr_c(
+    odrpack_fcn fcn,
+    int n,
+    int m,
+    int np,
+    int nq,
+    double *beta,
+    const double *y,
+    const double *x);
diff --git a/src/odrpack_capi.f90 b/c/odrpack_c.f90
similarity index 97%
rename from src/odrpack_capi.f90
rename to c/odrpack_c.f90
index 0486ead..b21b794 100644
--- a/src/odrpack_capi.f90
+++ b/c/odrpack_c.f90
@@ -1,10 +1,12 @@
-module odrpack_capi
-   use, intrinsic :: iso_c_binding, only : c_int, c_double, c_funptr, c_ptr, c_f_procpointer
+module odrpack_c
+   use, intrinsic :: iso_c_binding, only : c_int, c_double
    use odrpack, only: odr
    use odrpack_kinds, only: wp
    implicit none
    private
 
+   public :: odr_c
+
    abstract interface
       subroutine fcn_tc(n, m, np, nq, ldn, ldm, ldnp, beta, xplusd, ifixb, ifixx, ldifx, &
                         ideval, f, fjacb, fjacd, istop) bind(c)
@@ -27,11 +29,34 @@ subroutine fcn_tc(n, m, np, nq, ldn, ldm, ldnp, beta, xplusd, ifixb, ifixx, ldif
             real(c_double), intent(out) :: fjacb(ldn, ldnp, nq)
             real(c_double), intent(out) :: fjacd(ldn, ldm, nq)
             integer(c_int), intent(out) :: istop
-      end subroutine fcn_tc
+      end subroutine
    end interface
 
 contains
 
+   subroutine odr_c(fcn, n, m, np, nq, beta, y, x) bind(c)
+      !! "Short" wrapper for the ODR routine including only mandatory arguments.
+      procedure(fcn_tc) :: fcn
+         !! User-supplied subroutine for evaluating the model.
+      integer(c_int), intent(in), value :: n
+         !! Number of observations.
+      integer(c_int), intent(in), value :: m
+         !! Number of columns of data in the independent variable.
+      integer(c_int), intent(in), value :: np
+         !! Number of function parameters.
+      integer(c_int), intent(in), value :: nq
+         !! Number of responses per observation.
+      real(c_double), intent(inout) :: beta(np)
+         !! Function parameters.
+      real(c_double), intent(in) :: y(n, nq)
+         !! Dependent variable. Unused when the model is implicit.
+      real(c_double), intent(in) :: x(n, m)
+         !! Explanatory variable.      
+
+      call odr(fcn, n, m, np, nq, beta, y, x)
+
+   end subroutine odr_c
+
    ! subroutine odr_c( &
    !    fcn, &
    !    n, m, np, nq, &
@@ -118,27 +143,4 @@ end subroutine fcn_tc
    
    ! end subroutine
 
-   subroutine odr_c(fcn, n, m, np, nq, beta, y, x) bind(c)
-      !! "Short" wrapper for the ODR routine including only mandatory arguments.
-      procedure(fcn_tc) :: fcn
-         !! User-supplied subroutine for evaluating the model.
-      integer(c_int), intent(in), value :: n
-         !! Number of observations.
-      integer(c_int), intent(in), value :: m
-         !! Number of columns of data in the independent variable.
-      integer(c_int), intent(in), value :: np
-         !! Number of function parameters.
-      integer(c_int), intent(in), value :: nq
-         !! Number of responses per observation.
-      real(c_double), intent(inout) :: beta(np)
-         !! Function parameters.
-      real(c_double), intent(in) :: y(n, nq)
-         !! Dependent variable. Unused when the model is implicit.
-      real(c_double), intent(in) :: x(n, m)
-         !! Explanatory variable.      
-   
-      call odr(fcn, n, m, np, nq, beta, y, x)
-   
-   end subroutine
-
-end module odrpack_capi
\ No newline at end of file
+end module odrpack_c
\ No newline at end of file