diff --git a/ctpv.c b/ctpv.c
index e7acf07..e0d0154 100644
--- a/ctpv.c
+++ b/ctpv.c
@@ -53,7 +53,7 @@ static void init_previews_v(void)
     init_previews(previews, LEN(previews));
 }
 
-static const char *get_mimetype(char const *path)
+static const char *get_mimetype(const char *path)
 {
     const char *r = magic_file(magic, path);
     if (!r) {
@@ -64,7 +64,7 @@ static const char *get_mimetype(char const *path)
     return r;
 }
 
-static const char *get_ext(char const *path)
+static const char *get_ext(const char *path)
 {
     const char *base;
 
@@ -80,7 +80,7 @@ static const char *get_ext(char const *path)
     return &dot[1];
 }
 
-static int check_file(char const *f)
+static int check_file(const char *f)
 {
     if (!f) {
         print_error("file not given");
@@ -268,7 +268,7 @@ static int list(void)
 
 static int mime(int argc, char *argv[])
 {
-    char const *f, *mimetype;
+    const char *f, *mimetype;
 
     for (int i = 0; i < argc; i++) {
         f = argv[i];
diff --git a/error.c b/error.c
index d25a0ae..39a5618 100644
--- a/error.c
+++ b/error.c
@@ -3,12 +3,12 @@
 #include "error.h"
 #include "utils.h"
 
-void print_error(char const *error_msg)
+void print_error(const char *error_msg)
 {
     fprintf(stderr, "%s: %s\n", program, error_msg);
 }
 
-void print_errorf(char const *format, ...)
+void print_errorf(const char *format, ...)
 {
     char s[1024];
     FORMATTED_STRING(s, format);
diff --git a/error.h b/error.h
index 68f1e94..c9ae3b5 100644
--- a/error.h
+++ b/error.h
@@ -56,7 +56,7 @@ enum {
     ERR,
 };
 
-void print_error(char const *error_msg);
-void print_errorf(char const *format, ...);
+void print_error(const char *error_msg);
+void print_errorf(const char *format, ...);
 
 #endif
diff --git a/preview.c b/preview.c
index c31d570..fd7dc94 100644
--- a/preview.c
+++ b/preview.c
@@ -81,7 +81,7 @@ static void break_mimetype(char *mimetype, char **type, char **subtype)
 
 #define MIMETYPE_MAX 64
 
-static Preview *find_preview(char const *mimetype, char const *ext, size_t *i)
+static Preview *find_preview(const char *mimetype, const char *ext, size_t *i)
 {
     Preview *p;
     char mimetype_c[MIMETYPE_MAX], *t, *s;
diff --git a/server.c b/server.c
index 6870f49..4e3c96c 100644
--- a/server.c
+++ b/server.c
@@ -134,7 +134,7 @@ static void get_fifo_name(char *buf, size_t len, const char *id_s)
     snprintf(buf, len-1, "/tmp/ctpvfifo.%s", id_s);
 }
 
-int server_listen(char const *id_s)
+int server_listen(const char *id_s)
 {
     int ret = OK;
 
diff --git a/server.h b/server.h
index c589162..5044916 100644
--- a/server.h
+++ b/server.h
@@ -1,7 +1,7 @@
 #ifndef SERVER_H
 #define SERVER_H
 
-int server_listen(char const *id_s);
+int server_listen(const char *id_s);
 int server_set_fifo_var(const char *id_s);
 int server_clear(const char *id_s);
 int server_end(const char *id_s);
diff --git a/utils.c b/utils.c
index 49222fb..ef5b01b 100644
--- a/utils.c
+++ b/utils.c
@@ -70,7 +70,7 @@ int spawn(char *args[], pid_t *cpid, int *exitcode, int (*cfunc)(const void *),
     return OK;
 }
 
-int strcmpnull(char const *s1, char const *s2)
+int strcmpnull(const char *s1, const char *s2)
 {
     if (!s1 && !s2)
         return 0;
@@ -82,7 +82,7 @@ int strcmpnull(char const *s1, char const *s2)
     return strcmp(s1, s2);
 }
 
-int strlennull(char const *s)
+int strlennull(const char *s)
 {
     return s ? strlen(s) : 0;
 }
diff --git a/utils.h b/utils.h
index 58fa8b0..78eb245 100644
--- a/utils.h
+++ b/utils.h
@@ -28,8 +28,8 @@ int spawn_wait(pid_t pid, int *exitcode);
 int spawn(char *args[], pid_t *cpid, int *exitcode, int (*cfunc)(const void *),
           const void *carg);
 
-int strcmpnull(char const *s1, char const *s2);
-int strlennull(char const *s);
+int strcmpnull(const char *s1, const char *s2);
+int strlennull(const char *s);
 
 int get_cache_dir(char *buf, size_t len, char *name);
 int mkpath(char* file_path, mode_t mode);