diff --git a/qpms/beyn.h b/qpms/beyn.h
index 9395265..9b05a3a 100644
--- a/qpms/beyn.h
+++ b/qpms/beyn.h
@@ -3,6 +3,9 @@
  */
 #ifndef BEYN_H
 #define BEYN_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include <stddef.h>
 
@@ -47,12 +50,12 @@ typedef enum {
 /// Complex plane "half-elliptic" integration contour with axes parallel to the real, imaginary axes.
 /** Free using free(). */
 beyn_contour_t *beyn_contour_halfellipse(_Complex double centre, double halfax_re, double halfax_im, size_t npoints,
-		beyn_contour_halfellipse_orientation or);
+		beyn_contour_halfellipse_orientation o);
 
 /// Similar to halfellipse but with rounded corners.
 beyn_contour_t *beyn_contour_kidney(_Complex double centre, double halfax_re, double halfax_im, 
 	double rounding, ///< Must be in interval [0, 0.5)
-	size_t n, beyn_contour_halfellipse_orientation or);
+	size_t n, beyn_contour_halfellipse_orientation o);
 
 
 /// Beyn algorithm result structure (pure C array version).
@@ -82,4 +85,7 @@ beyn_result_t *beyn_solve(
 		double res_tol ///< (default: `0.0`) TODO DOC.
 	      );
 
+#ifdef __cplusplus
+}
+#endif
 #endif // BEYN_H
diff --git a/qpms/ewald.h b/qpms/ewald.h
index cb0acbe..4d0ac98 100644
--- a/qpms/ewald.h
+++ b/qpms/ewald.h
@@ -26,6 +26,10 @@
 
 #ifndef EWALD_H
 #define EWALD_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <gsl/gsl_sf_result.h>
 #include <stdlib.h>
 #include <gsl/gsl_sf_legendre.h>
@@ -335,4 +339,8 @@ int ewald3_sigma_long( // calls ewald3_21_sigma_long or ewald3_3_sigma_long, dep
 extern int ewald_factor_ipow_l;
 // If nonzero, adds an additional factor \f$ i^{nm} \f$ to the Ewald sum result (for debubbing).
 extern int ewald_factor_ipow_m;
+
+#ifdef __cplusplus
+}
+#endif
 #endif //EWALD_H
diff --git a/qpms/gaunt.h b/qpms/gaunt.h
index 425c660..d6e2e81 100644
--- a/qpms/gaunt.h
+++ b/qpms/gaunt.h
@@ -3,6 +3,10 @@
  */
 #ifndef GAUNT_H
 #define GAUNT_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <stdlib.h>
 
 #define _GAUNT_H_MIN(x,y) (((x) > (y)) ? (y) : (x))
@@ -30,4 +34,7 @@ double const * gaunt_table_retrieve_allq(int m, int n, int mu, int nu);
 int gaunt_table_or_xu_fill(double *target, int m, int n, int mu, int nu);
 #endif //GAUNT_PRECOMPILED
 
+#ifdef __cplusplus
+}
+#endif
 #endif //GAUNT_H
diff --git a/qpms/groups.h b/qpms/groups.h
index 771a7e9..36142d9 100644
--- a/qpms/groups.h
+++ b/qpms/groups.h
@@ -23,6 +23,9 @@
  */
 #ifndef QPMS_GROUPS_H
 #define QPMS_GROUPS_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include "qpms_types.h"
 #include <assert.h>
@@ -93,4 +96,7 @@ qpms_iri_t qpms_finite_group_find_irrep_by_name(qpms_finite_group_t *G, char *na
 extern const qpms_finite_group_t QPMS_FINITE_GROUP_TRIVIAL;
 extern const qpms_finite_group_t QPMS_FINITE_GROUP_TRIVIAL_G;
 
+#ifdef __cplusplus
+}
+#endif
 #endif // QPMS_GROUPS_H
diff --git a/qpms/indexing.h b/qpms/indexing.h
index aab7478..86ea952 100644
--- a/qpms/indexing.h
+++ b/qpms/indexing.h
@@ -26,6 +26,9 @@
  */
 #ifndef QPMS_INDEXING_H
 #define QPMS_INDEXING_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include "qpms_types.h"
 #include <math.h>
@@ -147,4 +150,7 @@ static inline qpms_m_t qpms_uvswfi2m(qpms_uvswfi_t u) {
 }
 
 
+#ifdef __cplusplus
+}
+#endif
 #endif //QPMS_INDEXING_H
diff --git a/qpms/kahansum.h b/qpms/kahansum.h
index 350bfa9..c2ef963 100644
--- a/qpms/kahansum.h
+++ b/qpms/kahansum.h
@@ -3,6 +3,9 @@
  */
 #ifndef KAHANSUM_H
 #define KAHANSUM_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 static inline void kahaninit(double * const sum, double * const compensation) {
 	*sum = 0;
@@ -29,4 +32,7 @@ static inline void ckahanadd(_Complex double *sum, _Complex double *compensation
 	*sum = nsum;
 }
 
+#ifdef __cplusplus
+}
+#endif
 #endif //KAHANSUM_H
diff --git a/qpms/lattices.h b/qpms/lattices.h
index d7daa3c..c41e479 100644
--- a/qpms/lattices.h
+++ b/qpms/lattices.h
@@ -4,6 +4,9 @@
  */
 #ifndef LATTICES_H
 #define LATTICES_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include <math.h>
 #include <stdbool.h>
@@ -945,4 +948,7 @@ int honeycomb_lattice_gen_extend_to_steps(honeycomb_lattice_gen_t *g, int maxste
 int honeycomb_lattice_gen_extend_to_r(honeycomb_lattice_gen_t *g, double r);
 void honeycomb_lattice_gen_free(honeycomb_lattice_gen_t *g);
 
+#ifdef __cplusplus
+}
+#endif
 #endif // LATTICES_H
diff --git a/qpms/materials.h b/qpms/materials.h
index d01885f..c14e041 100644
--- a/qpms/materials.h
+++ b/qpms/materials.h
@@ -3,6 +3,10 @@
  */
 #ifndef QPMS_MATERIALS_H
 #define QPMS_MATERIALS_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "qpms_types.h"
 #include <complex.h>
 #include <gsl/gsl_spline.h>
@@ -159,4 +163,7 @@ static inline _Complex double qpms_drude_epsilon(
 }
 
 
+#ifdef __cplusplus
+}
+#endif
 #endif //QPMS_MATERIALS_H
diff --git a/qpms/normalisation.h b/qpms/normalisation.h
index 6afa7ac..2b72f82 100644
--- a/qpms/normalisation.h
+++ b/qpms/normalisation.h
@@ -5,6 +5,9 @@
  */
 #ifndef NORMALISATION_H
 #define NORMALISATION_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include "qpms_types.h"
 #include "qpms_error.h"
@@ -282,4 +285,7 @@ static inline double qpms_normalisation_t_factor_abssquare(qpms_normalisation_t
 }
 #endif
 
+#ifdef __cplusplus
+}
+#endif
 #endif //NORMALISATION_H
diff --git a/qpms/parsing.h b/qpms/parsing.h
index 3f60daa..aba1f30 100644
--- a/qpms/parsing.h
+++ b/qpms/parsing.h
@@ -3,6 +3,9 @@
  */
 #ifndef QPMS_PARSING_H
 #define QPMS_PARSING_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include <stddef.h>
 
@@ -57,4 +60,7 @@ size_t qpms_parse_doubles_fromfile(
   const char *filepath //< File to read from, or NULL, "", "-" to read from stdin.
 );
 
+#ifdef __cplusplus
+}
+#endif
 #endif // QPMS_PARSING_H
diff --git a/qpms/pointgroups.h b/qpms/pointgroups.h
index 2823d47..2ddcac2 100644
--- a/qpms/pointgroups.h
+++ b/qpms/pointgroups.h
@@ -3,6 +3,9 @@
  */
 #ifndef POINTGROUPS_H
 #define POINTGROUPS_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include "qpms_error.h"
 #include "quaternions.h"
@@ -81,4 +84,7 @@ _Bool qpms_pg_is_subgroup(qpms_pointgroup_t a, qpms_pointgroup_t b);
 
 
 
+#ifdef __cplusplus
+}
+#endif
 #endif //POINTGROUPS_H
diff --git a/qpms/qpms_error.h b/qpms/qpms_error.h
index f554035..bb30c5c 100644
--- a/qpms/qpms_error.h
+++ b/qpms/qpms_error.h
@@ -5,6 +5,9 @@
  */
 #ifndef QPMS_ERROR_H
 #define QPMS_ERROR_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include "optim.h"
 
@@ -266,4 +269,7 @@ qpms_dbgmsg_flags qpms_dbgmsg_enable(qpms_dbgmsg_flags types);
 	}\
 }
 
+#ifdef __cplusplus
+}
+#endif
 #endif 
diff --git a/qpms/qpms_specfunc.h b/qpms/qpms_specfunc.h
index 6a9b32f..213a38d 100644
--- a/qpms/qpms_specfunc.h
+++ b/qpms/qpms_specfunc.h
@@ -3,6 +3,10 @@
  */
 #ifndef QPMS_SPECFUNC_H
 #define QPMS_SPECFUNC_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "qpms_types.h"
 #include <gsl/gsl_sf_legendre.h>
 
@@ -107,4 +111,7 @@ double qpms_legendre0(int m, int n);
 // Associated Legendre polynomial derivative at zero argument (DLMF 14.5.2)
 double qpms_legendred0(int m, int n);
 
+#ifdef __cplusplus
+}
+#endif
 #endif // QPMS_SPECFUNC_H
diff --git a/qpms/qpms_types.h b/qpms/qpms_types.h
index 75aeaca..209d07e 100644
--- a/qpms/qpms_types.h
+++ b/qpms/qpms_types.h
@@ -3,6 +3,10 @@
  */
 #ifndef QPMS_TYPES_H
 #define QPMS_TYPES_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <stddef.h>
 #include <stdint.h>
 #include <stdbool.h>
@@ -435,4 +439,8 @@ typedef enum {
 } qpms_ewald_part;
 
 #define lmcheck(l,m) assert((l) >= 1 && abs(m) <= (l))
+
+#ifdef __cplusplus
+}
+#endif
 #endif // QPMS_TYPES
diff --git a/qpms/qpmsblas.h b/qpms/qpmsblas.h
index c32282b..3981b82 100644
--- a/qpms/qpmsblas.h
+++ b/qpms/qpmsblas.h
@@ -14,6 +14,10 @@
  */
 #ifndef QPMSBLAS_H
 #define QPMSBLAS_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define QPMS_BLAS_INDEX_T long long int
 
 #ifndef CBLAS_H
@@ -31,4 +35,7 @@ void qpms_zgemm(CBLAS_LAYOUT Order, CBLAS_TRANSPOSE TransA, CBLAS_TRANSPOSE Tran
 		const _Complex double *B, const QPMS_BLAS_INDEX_T ldb,
 		const _Complex double *beta, _Complex double *C, const QPMS_BLAS_INDEX_T ldc);
 
+#ifdef __cplusplus
+}
+#endif
 #endif //QPMSBLAS_H
diff --git a/qpms/quaternions.h b/qpms/quaternions.h
index 520d821..474b06b 100644
--- a/qpms/quaternions.h
+++ b/qpms/quaternions.h
@@ -3,6 +3,9 @@
  */
 #ifndef QPMS_WIGNER_H
 #define QPMS_WIGNER_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include "qpms_types.h"
 #include "vectors.h"
@@ -303,4 +306,7 @@ static inline qpms_irot3_t qpms_irot3_zrot_Nk(double N, double k) {
 	return qpms_irot3_zrot_angle(2 * M_PI * k / N);
 }
 
+#ifdef __cplusplus
+}
+#endif
 #endif //QPMS_WIGNER_H
diff --git a/qpms/scatsystem.h b/qpms/scatsystem.h
index 7449ede..eb3337d 100644
--- a/qpms/scatsystem.h
+++ b/qpms/scatsystem.h
@@ -10,6 +10,10 @@
  */
 #ifndef QPMS_SCATSYSTEM_H
 #define QPMS_SCATSYSTEM_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "qpms_types.h"
 #include "vswf.h"
 #include "tmatrices.h"
@@ -919,4 +923,7 @@ ccart3_t qpms_scatsys_scattered_E_irrep(const qpms_scatsys_t *ss,
 		);
 #endif
 
+#ifdef __cplusplus
+}
+#endif
 #endif //QPMS_SCATSYSTEM_H
diff --git a/qpms/symmetries.h b/qpms/symmetries.h
index 3e590a3..4ef1f4d 100644
--- a/qpms/symmetries.h
+++ b/qpms/symmetries.h
@@ -21,6 +21,10 @@
  */
 #ifndef SYMMETRIES_H
 #define SYMMETRIES_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "qpms_types.h"
 #include <cblas.h>
 
@@ -75,4 +79,8 @@ size_t qpms_zero_roundoff_clean(double *arr, size_t nmemb, double atol);
  * TODO doc.
  */
 size_t qpms_czero_roundoff_clean(_Complex double *arr, size_t nmemb, double atol);
+
+#ifdef __cplusplus
+}
+#endif
 #endif // SYMMETRIES_H
diff --git a/qpms/tmatrices.h b/qpms/tmatrices.h
index b46571e..30361c9 100644
--- a/qpms/tmatrices.h
+++ b/qpms/tmatrices.h
@@ -3,6 +3,10 @@
  */
 #ifndef TMATRICES_H
 #define TMATRICES_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // #include "qpms_types.h" // included via materials.h
 // #include <gsl/gsl_spline.h> // included via materials.h
 #include "materials.h"
@@ -689,4 +693,7 @@ typedef struct qpms_abstract_particle_t {
 typedef qpms_particle_tid_t qpms_abstract_particle_tid_t;
 #endif // 0
 
+#ifdef __cplusplus
+}
+#endif
 #endif //TMATRICES_H
diff --git a/qpms/tolerances.h b/qpms/tolerances.h
index 14939a6..eac65df 100644
--- a/qpms/tolerances.h
+++ b/qpms/tolerances.h
@@ -1,6 +1,9 @@
 /*! \file tolerances.h */
 #ifndef QPMS_TOLERANCES_H
 #define QPMS_TOLERANCES_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 // TODO DOC
 
@@ -12,4 +15,7 @@ typedef struct qpms_tolerance_spec_t {
 /// A rather arbitrary default tolerance.
 static const qpms_tolerance_spec_t QPMS_TOLERANCE_DEFAULT = {.atol = 1e-9, .rtol =  1e-8};
 
+#ifdef __cplusplus
+}
+#endif
 #endif // QPMS_TOLERANCES_H
diff --git a/qpms/translations.h b/qpms/translations.h
index c5a3155..492a9c9 100644
--- a/qpms/translations.h
+++ b/qpms/translations.h
@@ -26,6 +26,10 @@
  */
 #ifndef QPMS_TRANSLATIONS_H
 #define QPMS_TRANSLATIONS_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "vectors.h"
 #include "qpms_types.h"
 #include <stdbool.h>
@@ -243,4 +247,7 @@ int qpms_cython_trans_calculator_get_AB_arrays_loop(
 #endif //QPMS_COMPILE_PYTHON_EXTENSIONS
 
 
+#ifdef __cplusplus
+}
+#endif
 #endif // QPMS_TRANSLATIONS_H
diff --git a/qpms/vswf.h b/qpms/vswf.h
index 736e803..86e68aa 100644
--- a/qpms/vswf.h
+++ b/qpms/vswf.h
@@ -7,6 +7,10 @@
  */
 #ifndef QPMS_VSWF_H
 #define QPMS_VSWF_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <unistd.h> // ssize_t 
 #include "qpms_types.h"
 #include <gsl/gsl_sf_legendre.h>
@@ -246,4 +250,7 @@ qpms_vswfset_sph_t *qpms_vswfset_make(qpms_l_t lMax, sph_t kdlj,
 		qpms_bessel_t btyp, qpms_normalisation_t norm);//NI
 void qpms_vswfset_sph_pfree(qpms_vswfset_sph_t *);//NI
 
+#ifdef __cplusplus
+}
+#endif
 #endif // QPMS_VSWF_H