diff --git a/examples/benchmark_write.c b/examples/benchmark_write.c
index f1e6efc..4c92f04 100644
--- a/examples/benchmark_write.c
+++ b/examples/benchmark_write.c
@@ -62,7 +62,7 @@ void flush_writes() {
 #endif
 }
 
-void delete_file(char* file_name) {
+void delete_file(const char* file_name) {
   char command[2048];
   snprintf(command, 2047, "rm %s", file_name);
   int rv = system(command);
diff --git a/examples/mtx2bsp.c b/examples/mtx2bsp.c
index 2ddc93b..7de6d8f 100644
--- a/examples/mtx2bsp.c
+++ b/examples/mtx2bsp.c
@@ -70,8 +70,8 @@ int main(int argc, char** argv) {
     compression_level = atoi(argv[4]);
   }
 
-  char* input_file_extension = bsp_get_file_extension(input_fname);
-  char* output_file_extension = bsp_get_file_extension(output_fname);
+  const char* input_file_extension = bsp_get_file_extension(input_fname);
+  const char* output_file_extension = bsp_get_file_extension(output_fname);
 
   if (input_file_extension == NULL ||
       strcmp(input_file_extension, ".mtx") != 0) {
diff --git a/examples/simple_matrix_read.c b/examples/simple_matrix_read.c
index 7d4c0c3..aaa8884 100644
--- a/examples/simple_matrix_read.c
+++ b/examples/simple_matrix_read.c
@@ -1,14 +1,14 @@
 #include <binsparse/binsparse.h>
 
 int main(int argc, char** argv) {
-  char* file_name = "test.hdf5";
+  const char* file_name = "test.hdf5";
 
   bsp_matrix_t mat = bsp_read_matrix(file_name, NULL);
 
   if (mat.format == BSP_COO) {
-    float* values = mat.values.data;
-    int* rowind = mat.indices_0.data;
-    int* colind = mat.indices_1.data;
+    float* values = (float*) mat.values.data;
+    int* rowind = (int*) mat.indices_0.data;
+    int* colind = (int*) mat.indices_1.data;
 
     for (size_t i = 0; i < mat.nnz; i++) {
       printf("%d, %d: %f\n", rowind[i], colind[i], values[i]);
diff --git a/examples/simple_matrix_write.c b/examples/simple_matrix_write.c
index 88ac963..bf551d2 100644
--- a/examples/simple_matrix_write.c
+++ b/examples/simple_matrix_write.c
@@ -7,9 +7,9 @@ int main(int argc, char** argv) {
 
   bsp_matrix_t mat = bsp_generate_coo(m, n, nnz, BSP_FLOAT32, BSP_INT32);
 
-  float* values = mat.values.data;
-  int* rowind = mat.indices_0.data;
-  int* colind = mat.indices_1.data;
+  float* values = (float*) mat.values.data;
+  int* rowind = (int*) mat.indices_0.data;
+  int* colind = (int*) mat.indices_1.data;
 
   for (size_t i = 0; i < nnz; i++) {
     printf("%d, %d: %f\n", rowind[i], colind[i], values[i]);
diff --git a/examples/simple_read.c b/examples/simple_read.c
index 94da3cf..225ea54 100644
--- a/examples/simple_read.c
+++ b/examples/simple_read.c
@@ -7,7 +7,7 @@ int main(int argc, char** argv) {
 
   bsp_array_t array = bsp_read_array(f, "test");
 
-  int* values = array.data;
+  int* values = (int*) array.data;
 
   for (size_t i = 0; i < array.size; i++) {
     printf("%lu: %d\n", i, values[i]);
diff --git a/examples/simple_write.c b/examples/simple_write.c
index e4f5952..15e3b36 100644
--- a/examples/simple_write.c
+++ b/examples/simple_write.c
@@ -1,13 +1,13 @@
 #include <binsparse/binsparse.h>
 
 int main(int argc, char** argv) {
-  char* file_name = "test.hdf5";
+  const char* file_name = "test.hdf5";
 
   hid_t f = H5Fcreate(file_name, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
 
   bsp_array_t array = bsp_construct_array_t(1000, BSP_INT32);
 
-  int* values = array.data;
+  int* values = (int*) array.data;
 
   for (size_t i = 0; i < array.size; i++) {
     bsp_array_write(array, i, i);
diff --git a/include/binsparse/detail/cpp/array.hpp b/include/binsparse/detail/cpp/array.hpp
index c351202..2c9d268 100644
--- a/include/binsparse/detail/cpp/array.hpp
+++ b/include/binsparse/detail/cpp/array.hpp
@@ -2,6 +2,7 @@
 
 #ifdef __cplusplus
 
+#include <string>
 #include <type_traits>
 #include <variant>
 
@@ -71,7 +72,7 @@ void bsp_array_read(bsp_array_t array, size_t index, T& value) {
       [&](auto* ptr) {
         using U = std::remove_pointer_t<decltype(ptr)>;
 
-        if constexpr (std::is_assignable_v<T, U>) {
+        if constexpr (std::is_assignable_v<T&, U>) {
           value = ptr[index];
         }
       },
@@ -87,7 +88,7 @@ void bsp_array_write(bsp_array_t array, size_t index, U value) {
       [&](auto* ptr) {
         using T = std::remove_pointer_t<decltype(ptr)>;
 
-        if constexpr (std::is_assignable_v<T, U>) {
+        if constexpr (std::is_assignable_v<T&, U>) {
           ptr[index] = value;
         }
       },
@@ -105,7 +106,7 @@ void bsp_array_awrite(bsp_array_t array_0, size_t index_0, bsp_array_t array_1,
         using T = std::remove_pointer_t<decltype(ptr_0)>;
         using U = std::remove_pointer_t<decltype(ptr_1)>;
 
-        if constexpr (std::is_assignable_v<T, U>) {
+        if constexpr (std::is_assignable_v<T&, U>) {
           ptr_0[index_0] = ptr_1[index_1];
         }
       },
diff --git a/include/binsparse/detail/parse_dataset.h b/include/binsparse/detail/parse_dataset.h
index 434c821..53123c8 100644
--- a/include/binsparse/detail/parse_dataset.h
+++ b/include/binsparse/detail/parse_dataset.h
@@ -35,7 +35,7 @@ bsp_fdataset_info_t bsp_parse_fdataset_string(char* str) {
   }
 }
 
-char* bsp_get_file_extension(char* file_name) {
+const char* bsp_get_file_extension(const char* file_name) {
   int64_t len = strlen(file_name);
   for (int64_t i = len - 1; i >= 0; i--) {
     if (file_name[i] == '.') {
diff --git a/include/binsparse/hdf5_wrapper.h b/include/binsparse/hdf5_wrapper.h
index b30b697..89e84e9 100644
--- a/include/binsparse/hdf5_wrapper.h
+++ b/include/binsparse/hdf5_wrapper.h
@@ -11,7 +11,7 @@
 
 // Write an array to a dataset / file
 // Returns 0 on success, nonzero on error.
-int bsp_write_array(hid_t f, char* label, bsp_array_t array,
+int bsp_write_array(hid_t f, const char* label, bsp_array_t array,
                     int compression_level) {
   if (array.type == BSP_COMPLEX_FLOAT32 || array.type == BSP_COMPLEX_FLOAT64) {
     array = bsp_complex_array_to_fp(array);
@@ -65,7 +65,8 @@ int bsp_write_array(hid_t f, char* label, bsp_array_t array,
   return 0;
 }
 
-bsp_array_t bsp_read_array_parallel(hid_t f, char* label, int num_threads) {
+bsp_array_t bsp_read_array_parallel(hid_t f, const char* label,
+                                    int num_threads) {
   hid_t dset = H5Dopen2(f, label, H5P_DEFAULT);
 
   if (dset == H5I_INVALID_HID) {
@@ -147,7 +148,7 @@ bsp_array_t bsp_read_array_parallel(hid_t f, char* label, int num_threads) {
   return array;
 }
 
-bsp_array_t bsp_read_array(hid_t f, char* label) {
+bsp_array_t bsp_read_array(hid_t f, const char* label) {
   hid_t dset = H5Dopen2(f, label, H5P_DEFAULT);
 
   if (dset == H5I_INVALID_HID) {
@@ -186,7 +187,7 @@ bsp_array_t bsp_read_array(hid_t f, char* label) {
   return array;
 }
 
-void bsp_write_attribute(hid_t f, char* label, char* string) {
+void bsp_write_attribute(hid_t f, const char* label, const char* string) {
   hid_t strtype = H5Tcopy(H5T_C_S1);
   H5Tset_size(strtype, strlen(string));
   H5Tset_cset(strtype, H5T_CSET_UTF8);
@@ -202,7 +203,7 @@ void bsp_write_attribute(hid_t f, char* label, char* string) {
   H5Sclose(dataspace);
 }
 
-char* bsp_read_attribute(hid_t f, char* label) {
+char* bsp_read_attribute(hid_t f, const char* label) {
   hid_t attribute = H5Aopen(f, label, H5P_DEFAULT);
   hid_t strtype = H5Aget_type(attribute);
 
diff --git a/include/binsparse/matrix_market/matrix_market_inspector.h b/include/binsparse/matrix_market/matrix_market_inspector.h
index ffac771..724b691 100644
--- a/include/binsparse/matrix_market/matrix_market_inspector.h
+++ b/include/binsparse/matrix_market/matrix_market_inspector.h
@@ -26,7 +26,7 @@ typedef struct bsp_mm_metadata {
   char* comments;
 } bsp_mm_metadata;
 
-bsp_mm_metadata bsp_mmread_metadata(char* file_path) {
+bsp_mm_metadata bsp_mmread_metadata(const char* file_path) {
   FILE* f = fopen(file_path, "r");
 
   assert(f != NULL);
diff --git a/include/binsparse/matrix_market/matrix_market_read.h b/include/binsparse/matrix_market/matrix_market_read.h
index e2e1fb3..d6745e4 100644
--- a/include/binsparse/matrix_market/matrix_market_read.h
+++ b/include/binsparse/matrix_market/matrix_market_read.h
@@ -9,7 +9,8 @@
 #include <binsparse/matrix_market/matrix_market_inspector.h>
 #include <binsparse/matrix_market/matrix_market_type_t.h>
 
-bsp_matrix_t bsp_mmread_explicit_array(char* file_path, bsp_type_t value_type,
+bsp_matrix_t bsp_mmread_explicit_array(const char* file_path,
+                                       bsp_type_t value_type,
                                        bsp_type_t index_type) {
   bsp_mm_metadata metadata = bsp_mmread_metadata(file_path);
 
@@ -96,7 +97,7 @@ bsp_matrix_t bsp_mmread_explicit_array(char* file_path, bsp_type_t value_type,
   return matrix;
 }
 
-bsp_matrix_t bsp_mmread_explicit_coordinate(char* file_path,
+bsp_matrix_t bsp_mmread_explicit_coordinate(const char* file_path,
                                             bsp_type_t value_type,
                                             bsp_type_t index_type) {
   bsp_mm_metadata metadata = bsp_mmread_metadata(file_path);
@@ -254,7 +255,7 @@ bsp_matrix_t bsp_mmread_explicit_coordinate(char* file_path,
   return matrix;
 }
 
-bsp_matrix_t bsp_mmread_explicit(char* file_path, bsp_type_t value_type,
+bsp_matrix_t bsp_mmread_explicit(const char* file_path, bsp_type_t value_type,
                                  bsp_type_t index_type) {
   bsp_mm_metadata metadata = bsp_mmread_metadata(file_path);
 
@@ -267,7 +268,7 @@ bsp_matrix_t bsp_mmread_explicit(char* file_path, bsp_type_t value_type,
   }
 }
 
-bsp_matrix_t bsp_mmread(char* file_path) {
+bsp_matrix_t bsp_mmread(const char* file_path) {
   bsp_mm_metadata metadata = bsp_mmread_metadata(file_path);
 
   bsp_type_t value_type;
diff --git a/include/binsparse/matrix_market/matrix_market_write.h b/include/binsparse/matrix_market/matrix_market_write.h
index 3446bda..75f9aeb 100644
--- a/include/binsparse/matrix_market/matrix_market_write.h
+++ b/include/binsparse/matrix_market/matrix_market_write.h
@@ -6,7 +6,7 @@
 
 #include <binsparse/matrix_market/matrix_market_type_t.h>
 
-void bsp_mmwrite(char* file_path, bsp_matrix_t matrix) {
+void bsp_mmwrite(const char* file_path, bsp_matrix_t matrix) {
   FILE* f = fopen(file_path, "w");
 
   assert(f != NULL);
diff --git a/include/binsparse/read_matrix.h b/include/binsparse/read_matrix.h
index 4a5339c..4664be0 100644
--- a/include/binsparse/read_matrix.h
+++ b/include/binsparse/read_matrix.h
@@ -209,7 +209,7 @@ bsp_matrix_t bsp_read_matrix_from_group(hid_t f) {
   return matrix;
 }
 
-size_t bsp_final_dot(char* str) {
+size_t bsp_final_dot(const char* str) {
   size_t dot_idx = 0;
   for (size_t i = 0; str[i] != '\0'; i++) {
     if (str[i] == '.') {
@@ -219,7 +219,7 @@ size_t bsp_final_dot(char* str) {
   return dot_idx;
 }
 
-bsp_matrix_t bsp_read_matrix_parallel(char* file_name, char* group,
+bsp_matrix_t bsp_read_matrix_parallel(const char* file_name, const char* group,
                                       int num_threads) {
   if (group == NULL) {
     size_t idx = bsp_final_dot(file_name);
@@ -244,7 +244,7 @@ bsp_matrix_t bsp_read_matrix_parallel(char* file_name, char* group,
   }
 }
 
-bsp_matrix_t bsp_read_matrix(char* file_name, char* group) {
+bsp_matrix_t bsp_read_matrix(const char* file_name, const char* group) {
   if (group == NULL) {
     size_t idx = bsp_final_dot(file_name);
     if (strcmp(file_name + idx, ".hdf5") == 0 ||
diff --git a/include/binsparse/write_matrix.h b/include/binsparse/write_matrix.h
index 0bd3657..76dd7c7 100644
--- a/include/binsparse/write_matrix.h
+++ b/include/binsparse/write_matrix.h
@@ -121,7 +121,7 @@ int bsp_write_matrix_to_group(hid_t f, bsp_matrix_t matrix, cJSON* user_json,
   return 0;
 }
 
-int bsp_write_matrix(char* fname, bsp_matrix_t matrix, char* group,
+int bsp_write_matrix(const char* fname, bsp_matrix_t matrix, const char* group,
                      cJSON* user_json, int compression_level) {
   if (group == NULL) {
     hid_t f = H5Fcreate(fname, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);