59 files changed, 295 insertions, 0 deletions

diff --git a/src/arch/arch.h b/src/arch/arch.h
index aa4a5c5..c4efbd5 100644
--- a/src/arch/arch.h
+++ b/src/arch/arch.h
@@ -1,3 +1,6 @@
+#ifndef ARCH_ARCH_H
+#define ARCH_ARCH_H
+
 #if defined(AVX2)
 
 #include <immintrin.h>
@@ -36,3 +39,5 @@ typedef struct {
 #endif
 
 #endif
+
+#endif /* ARCH_ARCH_H */
diff --git a/src/arch/avx2.h b/src/arch/avx2.h
index 801419e..5b9ecc7 100644
--- a/src/arch/avx2.h
+++ b/src/arch/avx2.h
@@ -1,3 +1,6 @@
+#ifndef ARCH_AVX2_H
+#define ARCH_AVX2_H
+
 #define CO2_AVX2 _mm256_set_epi64x(0, 0, 0, INT64_C(0x6060606060606060))
 #define COCW_AVX2 _mm256_set_epi64x(0, 0, 0, INT64_C(0x2020202020202020))
 #define CP_AVX2 _mm256_set_epi64x(0, 0, 0, INT64_C(0x0707070707070707))
@@ -478,3 +481,5 @@ invcoord_epudsep(uint64_t i)
 
         return _mm256_or_si256(elow, cube);
 }
+
+#endif /* ARCH_AVX2_H */
diff --git a/src/arch/common.h b/src/arch/common.h
index a7c4a3b..973263f 100644
--- a/src/arch/common.h
+++ b/src/arch/common.h
@@ -1,3 +1,6 @@
+#ifndef ARCH_COMMON_H
+#define ARCH_COMMON_H
+
 #define EOSHIFT     UINT8_C(4)
 #define COSHIFT     UINT8_C(5)
 
@@ -126,3 +129,5 @@ invcoord_epudsep_array(uint64_t c, uint8_t ret[8])
                 k -= is;
         }
 }
+
+#endif /* ARCH_COMMON_H */
diff --git a/src/arch/neon.h b/src/arch/neon.h
index 501b722..faf3b8f 100644
--- a/src/arch/neon.h
+++ b/src/arch/neon.h
@@ -1,3 +1,6 @@
+#ifndef ARCH_NEON_H
+#define ARCH_NEON_H
+
 #define CO2_NEON    vdup_n_u8(0x60)
 #define COCW_NEON   vdup_n_u8(0x20)
 #define EO_NEON     vdupq_n_u8(0x10)
@@ -557,3 +560,5 @@ invcoord_epudsep(uint64_t i)
                 .edge = vcombine_u8(vld1_u8(e), vld1_u8(SOLVED_H))
         };
 }
+
+#endif /* ARCH_NEON_H */
diff --git a/src/arch/portable.h b/src/arch/portable.h
index f1491f0..18fb6b8 100644
--- a/src/arch/portable.h
+++ b/src/arch/portable.h
@@ -1,3 +1,6 @@
+#ifndef ARCH_PORTABLE_H
+#define ARCH_PORTABLE_H
+
 #define STATIC_CUBE(c_ufr, c_ubl, c_dfl, c_dbr, c_ufl, c_ubr, c_dfr, c_dbl, \
     e_uf, e_ub, e_db, e_df, e_ur, e_ul, e_dl, e_dr, e_fr, e_fl, e_bl, e_br) \
     ((cube_t) { \
@@ -407,3 +410,5 @@ invcoord_epudsep(uint64_t c)
         invcoord_epudsep_array(c, ret.edge);
         return ret;
 }
+
+#endif /* ARCH_PORTABLE_H */
diff --git a/src/core/constants.h b/src/core/constants.h
index 076a483..7e51f67 100644
--- a/src/core/constants.h
+++ b/src/core/constants.h
@@ -1,3 +1,6 @@
+#ifndef CORE_CONSTANTS_H
+#define CORE_CONSTANTS_H
+
 #define ZERO_ORIENTED_CUBE ((oriented_cube_t) {0})
 #define SOLVED_ORIENTED_CUBE \
     ((oriented_cube_t) { .cube = SOLVED_CUBE, .orientation = 0 })
@@ -913,3 +916,5 @@ STATIC uint8_t basic_to_rotation[] = {
         [MOVE_B2] = MOVE_z2,
         [MOVE_B3] = MOVE_z,
 };
+
+#endif /* CORE_CONSTANTS_H */
diff --git a/src/core/core.h b/src/core/core.h
index 5e0faaa..d1c0ec1 100644
--- a/src/core/core.h
+++ b/src/core/core.h
@@ -1,6 +1,11 @@
+#ifndef CORE_CORE_H
+#define CORE_CORE_H
+
 #include "core_types.h"
 #include "constants.h"
 #include "cube.h"
 #include "moves.h"
 #include "transform.h"
 #include "oriented_cube.h"
+
+#endif /* CORE_CORE_H */
diff --git a/src/core/core_types.h b/src/core/core_types.h
index 53cc95e..6f69a8b 100644
--- a/src/core/core_types.h
+++ b/src/core/core_types.h
@@ -1,3 +1,6 @@
+#ifndef CORE_CORE_TYPES_H
+#define CORE_CORE_TYPES_H
+
 typedef struct {
         cube_t cube;
         uint8_t orientation;
@@ -9,3 +12,5 @@ typedef struct {
         uint8_t normal[NISSY_SIZE_MOVES];
         uint8_t inverse[NISSY_SIZE_MOVES];
 } moves_struct_t;
+
+#endif /* CORE_CORE_TYPES_H */
diff --git a/src/core/cube.h b/src/core/cube.h
index 1c21ce1..1dc6b61 100644
--- a/src/core/cube.h
+++ b/src/core/cube.h
@@ -1,3 +1,6 @@
+#ifndef CORE_CUBE_H
+#define CORE_CUBE_H
+
 STATIC bool cube_true(cube_t);
 
 STATIC cube_t cubefromarray(uint8_t [SIZE(8)], uint8_t [SIZE(12)]);
@@ -369,3 +372,5 @@ cornertob32(uint8_t corner)
 
         return val < 26 ? 'A' + (char)val : 'a' + (char)(val - 26);
 }
+
+#endif /* CORE_CUBE_H */
diff --git a/src/core/moves.h b/src/core/moves.h
index 9f1f7cc..19314de 100644
--- a/src/core/moves.h
+++ b/src/core/moves.h
@@ -1,3 +1,6 @@
+#ifndef CORE_MOVES_H
+#define CORE_MOVES_H
+
 #define MOVE(M, c) compose(c, MOVE_CUBE_ ## M)
 #define PREMOVE(M, c) compose(MOVE_CUBE_ ## M, c)
 
@@ -719,3 +722,5 @@ unniss_error:
         LOG("[variations] Error writing result.\n");
         return NISSY_ERROR_BUFFER_SIZE;
 }
+
+#endif /* CORE_MOVES_H */
diff --git a/src/core/oriented_cube.h b/src/core/oriented_cube.h
index 5449204..cc08736 100644
--- a/src/core/oriented_cube.h
+++ b/src/core/oriented_cube.h
@@ -1,3 +1,6 @@
+#ifndef CORE_ORIENTED_CUBE_H
+#define CORE_ORIENTED_CUBE_H
+
 STATIC oriented_cube_t solvedcube(void);
 
 STATIC oriented_cube_t move_extended(oriented_cube_t, uint8_t);
@@ -75,3 +78,5 @@ applymoves(oriented_cube_t cube, const char *buf)
         cinv.cube = inverse(cinv.cube);
         return compose_oriented(cinv, c);
 }
+
+#endif /* CORE_ORIENTED_CUBE_H */
diff --git a/src/core/transform.h b/src/core/transform.h
index af4634e..1c896e0 100644
--- a/src/core/transform.h
+++ b/src/core/transform.h
@@ -1,3 +1,6 @@
+#ifndef CORE_TRANSFORM_H
+#define CORE_TRANSFORM_H
+
 #define TRANS_EDGES_ROTATION(T, c) \
         compose_edges(compose_edges(TRANS_CUBE_ ## T, c), \
         TRANS_CUBE_ ## T ## _INVERSE)
@@ -418,3 +421,5 @@ symmetry_mask(cube_t cube)
 
         return ret;
 }
+
+#endif /* CORE_TRANSFORM_H */
diff --git a/src/solvers/coord/checkdata.h b/src/solvers/coord/checkdata.h
index 51265a8..a5d5316 100644
--- a/src/solvers/coord/checkdata.h
+++ b/src/solvers/coord/checkdata.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_CHECKDATA_H
+#define SOLVERS_COORD_CHECKDATA_H
+
 STATIC long long checkdata_coord_dispatch(
     const char *, unsigned long long, const unsigned char *);
 STATIC long long checkdata_coord(
@@ -120,3 +123,5 @@ checkdata_multicoord(
 
         return NISSY_OK;
 }
+
+#endif /* SOLVERS_COORD_CHECKDATA_H */
diff --git a/src/solvers/coord/common.h b/src/solvers/coord/common.h
index 3a62e85..8e6db20 100644
--- a/src/solvers/coord/common.h
+++ b/src/solvers/coord/common.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_COMMON_H
+#define SOLVERS_COORD_COMMON_H
+
 STATIC uint64_t coord_coord_generic(
     const coord_t [NON_NULL], cube_t, const unsigned char *);
 STATIC cube_t coord_cube_generic(
@@ -229,3 +232,5 @@ coordinate_merge_cpco(cube_t cp, cube_t co)
 
         return merged;
 }
+
+#endif /* SOLVERS_COORD_COMMON_H */
diff --git a/src/solvers/coord/coord.h b/src/solvers/coord/coord.h
index 98f4d05..6c4cc1b 100644
--- a/src/solvers/coord/coord.h
+++ b/src/solvers/coord/coord.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_COORD_H
+#define SOLVERS_COORD_COORD_H
+
 #include "types_macros.h"
 #include "common.h"
 #include "eo.h"
@@ -16,3 +19,5 @@
 #include "checkdata.h"
 #include "solve.h"
 #include "multisolve.h"
+
+#endif /* SOLVERS_COORD_COORD_H */
diff --git a/src/solvers/coord/corners.h b/src/solvers/coord/corners.h
index cc0d9a5..6dd60b5 100644
--- a/src/solvers/coord/corners.h
+++ b/src/solvers/coord/corners.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_CORNERS_H
+#define SOLVERS_COORD_CORNERS_H
+
 #define CLASSES_CP_48 984
 
 STATIC uint64_t coordinate_corners_coord(const cube_t, const unsigned char *);
@@ -70,3 +73,5 @@ coordinate_corners_gendata(unsigned char *data)
 {
         return coord_gendata_generic(&coordinate_corners, data);
 }
+
+#endif /* SOLVERS_COORD_CORNERS_H */
diff --git a/src/solvers/coord/cornersx.h b/src/solvers/coord/cornersx.h
index 788db8d..f4b564f 100644
--- a/src/solvers/coord/cornersx.h
+++ b/src/solvers/coord/cornersx.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_CORNERSX_H
+#define SOLVERS_COORD_CORNERSX_H
+
 STATIC bool is_cornersx_solved(uint64_t, const unsigned char *);
 
 STATIC coord_t coordinate_cornersx = {
@@ -74,3 +77,5 @@ is_cornersx_solved(uint64_t coord, const unsigned char *data)
 
         return false;
 }
+
+#endif /* SOLVERS_COORD_CORNERSX_H */
diff --git a/src/solvers/coord/cpepe.h b/src/solvers/coord/cpepe.h
index 7035400..1ad80dd 100644
--- a/src/solvers/coord/cpepe.h
+++ b/src/solvers/coord/cpepe.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_CPEPE_H
+#define SOLVERS_COORD_CPEPE_H
+
 STATIC uint64_t coordinate_cpepe_coord(const cube_t, const unsigned char *);
 STATIC cube_t coordinate_cpepe_cube(uint64_t, const unsigned char *);
 STATIC bool coordinate_cpepe_isnasty(uint64_t, const unsigned char *);
@@ -71,3 +74,5 @@ coordinate_cpepe_gendata(unsigned char *data)
 {
         return coord_gendata_generic(&coordinate_cpepe, data);
 }
+
+#endif /* SOLVERS_COORD_CPEPE_H */
diff --git a/src/solvers/coord/dr.h b/src/solvers/coord/dr.h
index 8100910..c5c73c2 100644
--- a/src/solvers/coord/dr.h
+++ b/src/solvers/coord/dr.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_DR_H
+#define SOLVERS_COORD_DR_H
+
 #define DREOESEP_CLASSES UINT64_C(64430)
 #define DREOESEP_MAX     (POW_2_11 * COMB_12_4)
 
@@ -117,3 +120,5 @@ is_eoco_solvable(cube_t cube) {
 
         return cocount % 3 == 0 && eocount % 2 == 0;
 }
+
+#endif /* SOLVERS_COORD_DR_H */
diff --git a/src/solvers/coord/dreo.h b/src/solvers/coord/dreo.h
index c5cacac..a201ae6 100644
--- a/src/solvers/coord/dreo.h
+++ b/src/solvers/coord/dreo.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_DREO_H
+#define SOLVERS_COORD_DREO_H
+
 #define DRESEP_CLASSES 81
 
 STATIC uint64_t coord_dresep_nosym(cube_t);
@@ -101,3 +104,5 @@ is_dreo_solvable(cube_t cube) {
 
         return cocount % 3 == 0;
 }
+
+#endif /* SOLVERS_COORD_DREO_H */
diff --git a/src/solvers/coord/drfin.h b/src/solvers/coord/drfin.h
index 569419b..ec645a2 100644
--- a/src/solvers/coord/drfin.h
+++ b/src/solvers/coord/drfin.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_DRFIN_H
+#define SOLVERS_COORD_DRFIN_H
+
 STATIC bool is_drfin_solvable(cube_t);
 
 STATIC multicoord_t multicoordinate_drfin = {
@@ -15,3 +18,5 @@ is_drfin_solvable(cube_t cube)
                coord_co(cube) == 0 &&
                issolvable((oriented_cube_t){.cube = cube, .orientation = 0});
 }
+
+#endif /* SOLVERS_COORD_DRFIN_H */
diff --git a/src/solvers/coord/drfinnoe.h b/src/solvers/coord/drfinnoe.h
index 63f4edf..5ffffc3 100644
--- a/src/solvers/coord/drfinnoe.h
+++ b/src/solvers/coord/drfinnoe.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_DRFINNOE_H
+#define SOLVERS_COORD_DRFINNOE_H
+
 /*
 TODO
 
@@ -96,3 +99,5 @@ is_drfinnoe_solvable(cube_t cube) {
                coord_eo(transform_edges(cube, TRANS_URr)) == 0 &&
                coord_co(cube) == 0;
 }
+
+#endif /* SOLVERS_COORD_DRFINNOE_H */
diff --git a/src/solvers/coord/drslice.h b/src/solvers/coord/drslice.h
index 42699f8..87bf87e 100644
--- a/src/solvers/coord/drslice.h
+++ b/src/solvers/coord/drslice.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_DRSLICE_H
+#define SOLVERS_COORD_DRSLICE_H
+
 /*
 The DRSLICE coordinate is almost identical to DRFINNOE, but it allows for
 the centers of the E layer to be off by a rotation. For this reason we reuse
@@ -95,3 +98,5 @@ is_drslice_solved(uint64_t i, const unsigned char *data)
         /* Pre-computed coordinates of U D' (= U' D up to trans) and U2 D2 */
         return i == 0 || i == 109779816 || i == 68468527;
 }
+
+#endif /* SOLVERS_COORD_DRSLICE_H */
diff --git a/src/solvers/coord/eo.h b/src/solvers/coord/eo.h
index 42196af..a5a0e85 100644
--- a/src/solvers/coord/eo.h
+++ b/src/solvers/coord/eo.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_EO_H
+#define SOLVERS_COORD_EO_H
+
 STATIC uint64_t coordinate_eo_coord(cube_t, const unsigned char *);
 STATIC cube_t coordinate_eo_cube(uint64_t, const unsigned char *);
 STATIC bool coordinate_eo_isnasty(uint64_t, const unsigned char *);
@@ -57,3 +60,5 @@ coordinate_eo_gendata(unsigned char *data)
 {
         return 0;
 }
+
+#endif /* SOLVERS_COORD_EO_H */
diff --git a/src/solvers/coord/gendata.h b/src/solvers/coord/gendata.h
index edf6ce6..0acf9c0 100644
--- a/src/solvers/coord/gendata.h
+++ b/src/solvers/coord/gendata.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_GENDATA_H
+#define SOLVERS_COORD_GENDATA_H
+
 STATIC size_t gendata_coord(const coord_t [NON_NULL], unsigned char *);
 STATIC size_t gendata_multicoord(
     const multicoord_t [NON_NULL], unsigned char *);
@@ -353,3 +356,5 @@ set_coord_pval(
         table[COORD_INDEX(i)] = (table[COORD_INDEX(i)] & (~COORD_MASK(i)))
             | (val << COORD_SHIFT(i));
 }
+
+#endif /* SOLVERS_COORD_GENDATA_H */
diff --git a/src/solvers/coord/htr.h b/src/solvers/coord/htr.h
index 602625b..d6fc311 100644
--- a/src/solvers/coord/htr.h
+++ b/src/solvers/coord/htr.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_HTR_H
+#define SOLVERS_COORD_HTR_H
+
 STATIC uint64_t coordinate_htr_coord(cube_t, const unsigned char *);
 STATIC cube_t coordinate_htr_cube(uint64_t, const unsigned char *);
 STATIC bool coordinate_htr_isnasty(uint64_t, const unsigned char *);
@@ -123,3 +126,5 @@ is_cp_htr(uint64_t i, const unsigned char *data)
 
         return e == 0 && is_cp16_htr_table[c / 8] & (UINT8_C(1) << (c % 8));
 }
+
+#endif /* SOLVERS_COORD_HTR_H */
diff --git a/src/solvers/coord/list.h b/src/solvers/coord/list.h
index 6856c13..71f7920 100644
--- a/src/solvers/coord/list.h
+++ b/src/solvers/coord/list.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_LIST_H
+#define SOLVERS_COORD_LIST_H
+
 coord_t *all_coordinates[] = {
         &coordinate_eo,
         &coordinate_dr,
@@ -15,3 +18,5 @@ multicoord_t *all_multicoordinates[] = {
         &multicoordinate_drfin,
         NULL
 };
+
+#endif /* SOLVERS_COORD_LIST_H */
diff --git a/src/solvers/coord/multisolve.h b/src/solvers/coord/multisolve.h
index efd287d..4990a39 100644
--- a/src/solvers/coord/multisolve.h
+++ b/src/solvers/coord/multisolve.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_MULTISOLVE_H
+#define SOLVERS_COORD_MULTISOLVE_H
+
 /*
 For now the only multicoordinate is DRFIN, and this solver reflects this.
 For example, NISS is not available.
@@ -297,3 +300,5 @@ solve_multicoord_error_unsolvable:
         LOG("[%s solve] Error: cube not ready\n", mcoord->name);
         return NISSY_ERROR_UNSOLVABLE_CUBE;
 }
+
+#endif /* SOLVERS_COORD_MULTISOLVE_H */
diff --git a/src/solvers/coord/solve.h b/src/solvers/coord/solve.h
index 6bb9af2..9a0c63c 100644
--- a/src/solvers/coord/solve.h
+++ b/src/solvers/coord/solve.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_SOLVE_H
+#define SOLVERS_COORD_SOLVE_H
+
 typedef struct {
         cube_t cube;
         cube_t inverse;
@@ -400,3 +403,5 @@ solve_coord_error_unsolvable:
         LOG("[%s solve] Error: cube not ready\n", coord->name);
         return NISSY_ERROR_UNSOLVABLE_CUBE;
 }
+
+#endif /* SOLVERS_COORD_SOLVE_H */
diff --git a/src/solvers/coord/types_macros.h b/src/solvers/coord/types_macros.h
index 81db9d4..b042788 100644
--- a/src/solvers/coord/types_macros.h
+++ b/src/solvers/coord/types_macros.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_TYPES_MACROS_H
+#define SOLVERS_COORD_TYPES_MACROS_H
+
 #define COORD_INDEX(i)      ((i)/2)
 #define COORD_SHIFT(i)      (UINT8_C(4) * (uint8_t)((i) % 2))
 #define COORD_MASK(i)       (UINT8_C(0xF) << COORD_SHIFT(i))
@@ -53,3 +56,5 @@ typedef struct {
         uint64_t moves_mask;
         bool (*is_solvable)(cube_t);
 } multicoord_t;
+
+#endif /* SOLVERS_COORD_TYPES_MACROS_H */
diff --git a/src/solvers/coord/utils.h b/src/solvers/coord/utils.h
index 0062587..232d6f8 100644
--- a/src/solvers/coord/utils.h
+++ b/src/solvers/coord/utils.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_COORD_UTILS_H
+#define SOLVERS_COORD_UTILS_H
+
 STATIC coord_t *parse_coord(size_t, const char *);
 STATIC multicoord_t *parse_multicoord(size_t, const char *);
 STATIC void parse_coord_and_trans(
@@ -80,3 +83,5 @@ dataid_coord(const char *ca, char dataid[SIZE(NISSY_SIZE_DATAID)])
         LOG("Error: cannot parse coordinate from '%s'\n", ca);
         return NISSY_ERROR_INVALID_SOLVER;
 }
+
+#endif /* SOLVERS_COORD_UTILS_H */
diff --git a/src/solvers/dispatch.h b/src/solvers/dispatch.h
index 810247f..d484736 100644
--- a/src/solvers/dispatch.h
+++ b/src/solvers/dispatch.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_DISPATCH_H
+#define SOLVERS_DISPATCH_H
+
 typedef struct {
         const char *solvername;
         const char *prefix;
@@ -92,3 +95,5 @@ match_solver(const char *name)
 
         return solver_dispatchers[i];
 }
+
+#endif /* SOLVERS_DISPATCH_H */
diff --git a/src/solvers/distribution.h b/src/solvers/distribution.h
index a996e3db..1ed7453 100644
--- a/src/solvers/distribution.h
+++ b/src/solvers/distribution.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_DISTRIBUTION_H
+#define SOLVERS_DISTRIBUTION_H
+
 #define ENTRIES_PER_BYTE(k) (UINT64_C(8) / (uint64_t)(k))
 #define TABLE_SHIFT(i, k)   ((uint8_t)(k) * (uint8_t)((i) % ENTRIES_PER_BYTE(k)))
 #define TABLE_MASK(i, k)    ((UINT8_BIT(k) - UINT8_C(1)) << TABLE_SHIFT(i, k))
@@ -99,3 +102,5 @@ distribution_equal(
 
         return wrong == 0;
 }
+
+#endif /* SOLVERS_DISTRIBUTION_H */
diff --git a/src/solvers/h48/checkdata.h b/src/solvers/h48/checkdata.h
index 948ac67..e2fa38c 100644
--- a/src/solvers/h48/checkdata.h
+++ b/src/solvers/h48/checkdata.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_CHECKDATA_H
+#define SOLVERS_H48_CHECKDATA_H
+
 STATIC long long checkdata_h48(
     const char *, unsigned long long, const unsigned char *);
 
@@ -194,3 +197,5 @@ checkdata_h48(
 
         return NISSY_OK;
 }
+
+#endif /* SOLVERS_H48_CHECKDATA_H */
diff --git a/src/solvers/h48/coordinate.h b/src/solvers/h48/coordinate.h
index 695efc3..acbb9c0 100644
--- a/src/solvers/h48/coordinate.h
+++ b/src/solvers/h48/coordinate.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_COORDINATE_H
+#define SOLVERS_H48_COORDINATE_H
+
 STATIC_INLINE uint64_t coord_h48(
     cube_t, const uint32_t [SIZE(COCSEP_TABLESIZE)], uint8_t);
 STATIC_INLINE uint64_t coord_h48_edges(cube_t, uint64_t, uint8_t, uint8_t);
@@ -68,3 +71,5 @@ invcoord_h48(
 
         return ret;
 }
+
+#endif /* SOLVERS_H48_COORDINATE_H */
diff --git a/src/solvers/h48/coordinate_types_macros.h b/src/solvers/h48/coordinate_types_macros.h
index cf24e47..6ddd3e8 100644
--- a/src/solvers/h48/coordinate_types_macros.h
+++ b/src/solvers/h48/coordinate_types_macros.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_COORDINATE_TYPES_MACROS_H
+#define SOLVERS_H48_COORDINATE_TYPES_MACROS_H
+
 #define H48_ESIZE(h) ((COMB_12_4 * COMB_8_4) << (uint64_t)(h))
 
 #define COCLASS_MASK (UINT32_C(0xFFFF) << UINT32_C(16))
@@ -5,3 +8,5 @@
 #define ECLASS(x)    COCLASS(x)
 #define TTREP_MASK   (UINT32_C(0xFF) << UINT32_C(8))
 #define TTREP(x)     (((x) & TTREP_MASK) >> UINT32_C(8))
+
+#endif /* SOLVERS_H48_COORDINATE_TYPES_MACROS_H */
diff --git a/src/solvers/h48/distribution_h48.h b/src/solvers/h48/distribution_h48.h
index 2cb50aa..b7f3811 100644
--- a/src/solvers/h48/distribution_h48.h
+++ b/src/solvers/h48/distribution_h48.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_DISTRIBUTION_H48_H
+#define SOLVERS_H48_DISTRIBUTION_H48_H
+
 /*
 This file is very similar to ../distibution.h, but some adaptations are
 needed for H48 because of the intertwined fallback table, and it is easier
@@ -74,3 +77,5 @@ getdistribution_h48(
         c = H48_LINE_EXT(H48_COORDMAX(info->h48h)) % H48_LINE_ALLCOORDS;
         distr[3] -= H48_LINE_COORDS - c;
 }
+
+#endif /* SOLVERS_H48_DISTRIBUTION_H48_H */
diff --git a/src/solvers/h48/gendata_cocsep.h b/src/solvers/h48/gendata_cocsep.h
index f83207b..1cea52e 100644
--- a/src/solvers/h48/gendata_cocsep.h
+++ b/src/solvers/h48/gendata_cocsep.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_GENDATA_COCSEP_H
+#define SOLVERS_H48_GENDATA_COCSEP_H
+
 STATIC size_t gendata_cocsep(unsigned char *, uint64_t *, cube_t *);
 STATIC uint32_t gendata_cocsep_dfs(cocsep_dfs_arg_t [NON_NULL]);
 
@@ -164,3 +167,5 @@ get_h48_cdata(
 
         return CBOUND(*cdata);
 }
+
+#endif /* SOLVERS_H48_GENDATA_COCSEP_H */
diff --git a/src/solvers/h48/gendata_eoesep.h b/src/solvers/h48/gendata_eoesep.h
index 81bbd43..55097c9 100644
--- a/src/solvers/h48/gendata_eoesep.h
+++ b/src/solvers/h48/gendata_eoesep.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_GENDATA_EOESEP_H
+#define SOLVERS_H48_GENDATA_EOESEP_H
+
 STATIC uint64_t coord_eoesep_sym(cube_t, const uint32_t [SIZE(ESEP_MAX)]);
 STATIC size_t gendata_esep_classes(
     uint32_t [SIZE(ESEP_MAX)], uint16_t [SIZE(ESEP_CLASSES)]);
@@ -280,3 +283,5 @@ set_eoesep_pval(
         table[EOESEP_INDEX(i)] = (table[EOESEP_INDEX(i)] & (~EOESEP_MASK(i)))
             | (val << EOESEP_SHIFT(i));
 }
+
+#endif /* SOLVERS_H48_GENDATA_EOESEP_H */
diff --git a/src/solvers/h48/gendata_h48.h b/src/solvers/h48/gendata_h48.h
index 53b1fad..0b85e49 100644
--- a/src/solvers/h48/gendata_h48.h
+++ b/src/solvers/h48/gendata_h48.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_GENDATA_H48_H
+#define SOLVERS_H48_GENDATA_H48_H
+
 STATIC long long gendata_h48_dispatch(
     const char *, unsigned long long, unsigned char *);
 STATIC uint64_t gendata_h48short(gendata_h48short_arg_t [NON_NULL]);
@@ -547,3 +550,5 @@ get_h48_pval_and_min(
         *pval_min = tmin >> UINT8_C(4);
         return (t & H48_MASK(iext)) >> H48_SHIFT(iext);
 }
+
+#endif /* SOLVERS_H48_GENDATA_H48_H */
diff --git a/src/solvers/h48/gendata_types_macros.h b/src/solvers/h48/gendata_types_macros.h
index 9bce2c9..e81acc5 100644
--- a/src/solvers/h48/gendata_types_macros.h
+++ b/src/solvers/h48/gendata_types_macros.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_GENDATA_TYPES_MACROS_H
+#define SOLVERS_H48_GENDATA_TYPES_MACROS_H
+
 #define COCSEP_CLASSES      ((size_t)3393)
 #define COCSEP_TABLESIZE    ((size_t)POW_3_7 << (size_t)7)
 #define COCSEP_VISITEDSIZE  DIV_ROUND_UP(COCSEP_TABLESIZE, (size_t)8)
@@ -116,3 +119,5 @@ typedef struct {
         wrapthread_atomic unsigned char *table_atomic;
         wrapthread_define_struct_mutex_t(**table_mutex);
 } gendata_h48_mark_t;
+
+#endif /* SOLVERS_H48_GENDATA_TYPES_MACROS_H */
diff --git a/src/solvers/h48/h48.h b/src/solvers/h48/h48.h
index f7ba8b7..e05fc2b 100644
--- a/src/solvers/h48/h48.h
+++ b/src/solvers/h48/h48.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_H48_H
+#define SOLVERS_H48_H48_H
+
 #include "utils.h"
 #include "coordinate_types_macros.h"
 #include "map_types_macros.h"
@@ -10,3 +13,5 @@
 #include "gendata_h48.h"
 #include "checkdata.h"
 #include "solve.h"
+
+#endif /* SOLVERS_H48_H48_H */
diff --git a/src/solvers/h48/map.h b/src/solvers/h48/map.h
index c9cfb06..75b5236 100644
--- a/src/solvers/h48/map.h
+++ b/src/solvers/h48/map.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_MAP_H
+#define SOLVERS_H48_MAP_H
+
 STATIC void h48map_create(h48map_t [NON_NULL], uint64_t, uint64_t);
 STATIC void h48map_clear(h48map_t [NON_NULL]);
 STATIC void h48map_destroy(h48map_t [NON_NULL]);
@@ -82,3 +85,5 @@ h48map_nextkvpair(h48map_t map[NON_NULL], uint64_t p[NON_NULL])
 
         return kv;
 }
+
+#endif /* SOLVERS_H48_MAP_H */
diff --git a/src/solvers/h48/map_types_macros.h b/src/solvers/h48/map_types_macros.h
index b77c68a..a4e3c75 100644
--- a/src/solvers/h48/map_types_macros.h
+++ b/src/solvers/h48/map_types_macros.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_MAP_TYPES_MACROS_H
+#define SOLVERS_H48_MAP_TYPES_MACROS_H
+
 #define MAP_UNSET             UINT64_C(0xFFFFFFFFFFFFFFFF)
 #define MAP_KEYMASK           UINT64_C(0xFFFFFFFFFF)
 #define MAP_KEYSHIFT          UINT64_C(40)
@@ -14,3 +17,5 @@ typedef struct {
         uint64_t key;
         uint64_t val;
 } kvpair_t;
+
+#endif /* SOLVERS_H48_MAP_TYPES_MACROS_H */
diff --git a/src/solvers/h48/solve.h b/src/solvers/h48/solve.h
index ebc5208..36fefa1 100644
--- a/src/solvers/h48/solve.h
+++ b/src/solvers/h48/solve.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_SOLVE_H
+#define SOLVERS_H48_SOLVE_H
+
 #define H48_STARTING_MOVES 4
 #define H48_STARTING_CUBES 43254
 #define H48_SORT_TASKS_MIN_DEPTH 16
@@ -758,3 +761,5 @@ solve_h48_error_data:
 solve_h48_error_solutions_buffer:
         return NISSY_ERROR_BUFFER_SIZE;
 }
+
+#endif /* SOLVERS_H48_SOLVE_H */
diff --git a/src/solvers/h48/utils.h b/src/solvers/h48/utils.h
index 6d91108..81c6451 100644
--- a/src/solvers/h48/utils.h
+++ b/src/solvers/h48/utils.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_H48_UTILS_H
+#define SOLVERS_H48_UTILS_H
+
 #if SIZE_MAX == UINT64_MAX
 #define H48_HMAX UINT8_C(11)
 #else
@@ -63,3 +66,5 @@ dataid_h48(const char *str, char buf[SIZE(NISSY_SIZE_DATAID)])
         sprintf(buf, "h48h%" PRIu8, h);
         return NISSY_OK;
 }
+
+#endif /* SOLVERS_H48_UTILS_H */
diff --git a/src/solvers/solutions.h b/src/solvers/solutions.h
index b7a848b..f9bed75 100644
--- a/src/solvers/solutions.h
+++ b/src/solvers/solutions.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_SOLUTIONS_H
+#define SOLVERS_SOLUTIONS_H
+
 STATIC void solution_moves_reset(solution_moves_t [NON_NULL]);
 STATIC void solution_moves_transform(solution_moves_t [NON_NULL], size_t,
     uint8_t);
@@ -338,3 +341,5 @@ solutions_done(
             depth > list->shortest_sol + settings->optimal ||
             list->nsols >= settings->maxsolutions;
 }
+
+#endif /* SOLVERS_SOLUTIONS_H */
diff --git a/src/solvers/solutions_types_macros.h b/src/solvers/solutions_types_macros.h
index 4727e5a..8454a21 100644
--- a/src/solvers/solutions_types_macros.h
+++ b/src/solvers/solutions_types_macros.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_SOLUTIONS_TYPES_MACROS_H
+#define SOLVERS_SOLUTIONS_TYPES_MACROS_H
+
 #define SOLUTION_MAXLEN 20
 
 typedef struct {
@@ -22,3 +25,5 @@ typedef struct {
         size_t used;
         char *buf;
 } solution_list_t;
+
+#endif /* SOLVERS_SOLUTIONS_TYPES_MACROS_H */
diff --git a/src/solvers/solvers.h b/src/solvers/solvers.h
index e19b08a..78180aa 100644
--- a/src/solvers/solvers.h
+++ b/src/solvers/solvers.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_SOLVERS_H
+#define SOLVERS_SOLVERS_H
+
 #include "solutions_types_macros.h"
 #include "solutions.h"
 #include "tables_types_macros.h"
@@ -6,3 +9,5 @@
 #include "coord/coord.h"
 #include "h48/h48.h"
 #include "dispatch.h"
+
+#endif /* SOLVERS_SOLVERS_H */
diff --git a/src/solvers/tables.h b/src/solvers/tables.h
index 3db1d1e..f850793 100644
--- a/src/solvers/tables.h
+++ b/src/solvers/tables.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_TABLES_H
+#define SOLVERS_TABLES_H
+
 STATIC uint64_t read_unaligned_u64(
     const unsigned char [SIZE(sizeof(uint64_t))]);
 STATIC void write_unaligned_u64(
@@ -147,3 +150,5 @@ append_name(tableinfo_t info[NON_NULL], const char *str)
 
         info->solver[j] = '\0';
 }
+
+#endif /* SOLVERS_TABLES_H */
diff --git a/src/solvers/tables_types_macros.h b/src/solvers/tables_types_macros.h
index b2809b7..8ae18d3 100644
--- a/src/solvers/tables_types_macros.h
+++ b/src/solvers/tables_types_macros.h
@@ -1,3 +1,6 @@
+#ifndef SOLVERS_TABLES_TYPES_MACROS_H
+#define SOLVERS_TABLES_TYPES_MACROS_H
+
 #define OFFSET(B, K)             (((unsigned char *)B) + K)
 
 #define INFOSIZE                 INT64_C(512)
@@ -37,3 +40,5 @@ typedef struct {
         uint8_t base;
         uint8_t maxvalue;
 } tableinfo_t;
+
+#endif /* SOLVERS_TABLES_TYPES_MACROS_H */
diff --git a/src/utils/compilers.h b/src/utils/compilers.h
index 1b175bb..a2ae3ba 100644
--- a/src/utils/compilers.h
+++ b/src/utils/compilers.h
@@ -1,3 +1,6 @@
+#ifndef UTILS_COMPILERS_H
+#define UTILS_COMPILERS_H
+
 #if defined(__GNUC__)
 
 #define UNUSED __attribute__((unused))
@@ -22,3 +25,5 @@ a[static N] notation for array parameters).
 #define NON_NULL
 
 #endif
+
+#endif /* UTILS_COMPILERS_H */
diff --git a/src/utils/constants.h b/src/utils/constants.h
index 3eed27d..3d0f6e3 100644
--- a/src/utils/constants.h
+++ b/src/utils/constants.h
@@ -1,3 +1,6 @@
+#ifndef UTILS_CONSTANTS_H
+#define UTILS_CONSTANTS_H
+
 #define UINT8_BIT(i) (UINT8_C(1) << (uint8_t)(i))
 
 #define FACTORIAL_MAX UINT64_C(12)
@@ -42,3 +45,5 @@ STATIC uint64_t binomial[12][12] = {
         {1, 10, 45, 120, 210, 252, 210, 120,  45, 10,  1, 0},
         {1, 11, 55, 165, 330, 462, 462, 330, 165, 55, 11, 1},
 };
+
+#endif /* UTILS_CONSTANTS_H */
diff --git a/src/utils/dbg_log.h b/src/utils/dbg_log.h
index 08d42a3..f22260a 100644
--- a/src/utils/dbg_log.h
+++ b/src/utils/dbg_log.h
@@ -1,3 +1,6 @@
+#ifndef UTILS_DBG_LOG_H
+#define UTILS_DBG_LOG_H
+
 #include <stdio.h>
 
 void (*nissy_log)(const char *, void *);
@@ -31,3 +34,5 @@ write_wrapper(void (*write)(const char *, void *), const char *str, ...)
 #define DBG_WARN(condition, ...)
 #define DBG_ASSERT(condition, ...)
 #endif
+
+#endif /* UTILS_DBG_LOG_H */
diff --git a/src/utils/math.h b/src/utils/math.h
index 0c56861..66ddaed 100644
--- a/src/utils/math.h
+++ b/src/utils/math.h
@@ -1,3 +1,6 @@
+#ifndef UTILS_MATH_H
+#define UTILS_MATH_H
+
 #define SWAP(x, y) do { x ^= y; y ^= x; x ^= y; } while (0)
 #define MIN(x, y) ((x) < (y) ? (x) : (y))
 #define MAX(x, y) ((x) > (y) ? (x) : (y))
@@ -146,3 +149,5 @@ intpow(double b, uint64_t e)
 
         return e % 2 == 0 ? r * r : b * r * r;
 }
+
+#endif /* UTILS_MATH_H */
diff --git a/src/utils/prefetch.h b/src/utils/prefetch.h
index a2c41ef..30e364e 100644
--- a/src/utils/prefetch.h
+++ b/src/utils/prefetch.h
@@ -1,3 +1,6 @@
+#ifndef UTILS_PREFETCH_H
+#define UTILS_PREFETCH_H
+
 #if defined(__GNUC__) || defined(__clang__)
     #define prefetch(a, i) __builtin_prefetch(a+i, 0, 0)
 #elif defined(AVX2)
@@ -5,3 +8,5 @@
 #else
     #define prefetch(a, i) (void)i
 #endif
+
+#endif /* UTILS_PREFETCH_H */
diff --git a/src/utils/sleep.h b/src/utils/sleep.h
index 7c0a84d..28bb807 100644
--- a/src/utils/sleep.h
+++ b/src/utils/sleep.h
@@ -1,3 +1,6 @@
+#ifndef UTILS_SLEEP_H
+#define UTILS_SLEEP_H
+
 #define BASE_SLEEP_TIME 500
 
 STATIC void msleep(int);
@@ -50,3 +53,5 @@ msleep(int milliseconds)
 }
 
 #endif
+
+#endif /* UTILS_SLEEP_H */
diff --git a/src/utils/utils.h b/src/utils/utils.h
index e322f20..e320105 100644
--- a/src/utils/utils.h
+++ b/src/utils/utils.h
@@ -1,3 +1,6 @@
+#ifndef UTILS_UTILS_H
+#define UTILS_UTILS_H
+
 #include "compilers.h"
 #include "dbg_log.h"
 #include "constants.h"
@@ -5,3 +8,5 @@
 #include "sleep.h"
 #include "wrapthread.h"
 #include "prefetch.h"
+
+#endif /* UTILS_UTILS_H */
diff --git a/src/utils/wrapthread.h b/src/utils/wrapthread.h
index 9578293..e88eb58 100644
--- a/src/utils/wrapthread.h
+++ b/src/utils/wrapthread.h
@@ -1,3 +1,6 @@
+#ifndef UTILS_WRAPTHREAD_H
+#define UTILS_WRAPTHREAD_H
+
 #if THREADS == 1
         #define WRAPTHREAD_NOTHREADS 1
 #elif defined(__unix__)
@@ -75,3 +78,5 @@
         #define wrapthread_mutex_unlock(a)
 
 #endif
+
+#endif /* UTILS_WRAPTHREAD_H */