diff --git a/builtin-fetch.c b/builtin-fetch.c
index 817dd6bff0bf0ddc9a3d00191bb3c422300b878b..cb48c57ca3e66b7ec39a98128b2cfb058c2dad15 100644
--- a/builtin-fetch.c
+++ b/builtin-fetch.c
@@ -454,7 +454,7 @@ static int quickfetch(struct ref *ref_map)
 
 	for (ref = ref_map; ref; ref = ref->next) {
 		if (write_in_full(revlist.in, sha1_to_hex(ref->old_sha1), 40) < 0 ||
-		    write_in_full(revlist.in, "\n", 1) < 0) {
+		    write_str_in_full(revlist.in, "\n") < 0) {
 			if (errno != EPIPE && errno != EINVAL)
 				error("failed write to rev-list: %s", strerror(errno));
 			err = -1;
diff --git a/builtin-reflog.c b/builtin-reflog.c
index 95198c5de41072bfb8adf7f29d9bbb44eec665ac..e23b5ef979d98e5e44693345856a13485695246f 100644
--- a/builtin-reflog.c
+++ b/builtin-reflog.c
@@ -362,7 +362,7 @@ static int expire_reflog(const char *ref, const unsigned char *sha1, int unused,
 		} else if (cmd->updateref &&
 			(write_in_full(lock->lock_fd,
 				sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
-			 write_in_full(lock->lock_fd, "\n", 1) != 1 ||
+			 write_str_in_full(lock->lock_fd, "\n") != 1 ||
 			 close_ref(lock) < 0)) {
 			status |= error("Couldn't write %s",
 				lock->lk->filename);
diff --git a/cache.h b/cache.h
index 5fad24ce219be746ad582d8432464753975f34fe..867918d0417642b7c1bb6ccb8f88730fdea08157 100644
--- a/cache.h
+++ b/cache.h
@@ -923,13 +923,18 @@ extern const char *git_mailmap_file;
 extern void maybe_flush_or_die(FILE *, const char *);
 extern int copy_fd(int ifd, int ofd);
 extern int copy_file(const char *dst, const char *src, int mode);
-extern ssize_t read_in_full(int fd, void *buf, size_t count);
-extern ssize_t write_in_full(int fd, const void *buf, size_t count);
 extern void write_or_die(int fd, const void *buf, size_t count);
 extern int write_or_whine(int fd, const void *buf, size_t count, const char *msg);
 extern int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg);
 extern void fsync_or_die(int fd, const char *);
 
+extern ssize_t read_in_full(int fd, void *buf, size_t count);
+extern ssize_t write_in_full(int fd, const void *buf, size_t count);
+static inline ssize_t write_str_in_full(int fd, const char *str)
+{
+	return write_in_full(fd, str, strlen(str));
+}
+
 /* pager.c */
 extern void setup_pager(void);
 extern const char *pager_program;
diff --git a/commit.c b/commit.c
index a6c6f70a9237385d163ea12ef28e5087e9f80411..fedbd5e5267ec4beaf1f245a879918a2685c10b9 100644
--- a/commit.c
+++ b/commit.c
@@ -212,7 +212,7 @@ int write_shallow_commits(int fd, int use_pack_protocol)
 			else {
 				if (write_in_full(fd, hex,  40) != 40)
 					break;
-				if (write_in_full(fd, "\n", 1) != 1)
+				if (write_str_in_full(fd, "\n") != 1)
 					break;
 			}
 		}
diff --git a/config.c b/config.c
index e87edeab0c6b9579ecbd9bc5a9a11c3522d21ccf..bf122202a014160321d97444a9b3bf2b546f6f3f 100644
--- a/config.c
+++ b/config.c
@@ -1116,7 +1116,7 @@ int git_config_set_multivar(const char *key, const char *value,
 				    copy_end - copy_begin)
 					goto write_err_out;
 				if (new_line &&
-				    write_in_full(fd, "\n", 1) != 1)
+				    write_str_in_full(fd, "\n") != 1)
 					goto write_err_out;
 			}
 			copy_begin = store.offset[i];
diff --git a/rerere.c b/rerere.c
index 87360dc23e54aabf47b3bda160e58058507d4a2f..29f95f657d04300e375d007e9d01832b89311602 100644
--- a/rerere.c
+++ b/rerere.c
@@ -61,7 +61,7 @@ static int write_rr(struct string_list *rr, int out_fd)
 		path = rr->items[i].string;
 		length = strlen(path) + 1;
 		if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
-		    write_in_full(out_fd, "\t", 1) != 1 ||
+		    write_str_in_full(out_fd, "\t") != 1 ||
 		    write_in_full(out_fd, path, length) != length)
 			die("unable to write rerere record");
 	}
diff --git a/upload-pack.c b/upload-pack.c
index c77ab710c459cb292ee2162919ed28e260e5da88..b3471e417de64fb6bef300923f4b2c1b6351fa6d 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -553,7 +553,7 @@ static void receive_needs(void)
 
 	shallow_nr = 0;
 	if (debug_fd)
-		write_in_full(debug_fd, "#S\n", 3);
+		write_str_in_full(debug_fd, "#S\n");
 	for (;;) {
 		struct object *o;
 		unsigned char sha1_buf[20];
@@ -619,7 +619,7 @@ static void receive_needs(void)
 		}
 	}
 	if (debug_fd)
-		write_in_full(debug_fd, "#E\n", 3);
+		write_str_in_full(debug_fd, "#E\n");
 
 	if (!use_sideband && daemon_mode)
 		no_progress = 1;