diff --git a/repl/main.c b/repl/main.c
index 499ddcf..efb71df 100644
--- a/repl/main.c
+++ b/repl/main.c
@@ -79,35 +79,32 @@ int getFileName(char* dest, const char* src, size_t destLength) {
 #undef MIN
 }
 
-//callbacks
-static void printCallback(const char* msg) {
-	fprintf(stdout, "%s\n", msg);
-}
-
-static void errorAndExitCallback(const char* msg) {
+//error callbacks
+static int errorAndExitCallback(const char* msg) {
 	fprintf(stderr, TOY_CC_ERROR "Error: %s" TOY_CC_RESET "\n", msg);
 	exit(-1);
 }
 
-static void errorAndContinueCallback(const char* msg) {
-	fprintf(stderr, TOY_CC_ERROR "Error: %s" TOY_CC_RESET "\n", msg);
+static int errorAndContinueCallback(const char* msg) {
+	return fprintf(stderr, TOY_CC_ERROR "Error: %s" TOY_CC_RESET "\n", msg);
 }
 
-static void assertFailureAndExitCallback(const char* msg) {
+static int assertFailureAndExitCallback(const char* msg) {
 	fprintf(stderr, TOY_CC_ASSERT "Assert Failure: %s" TOY_CC_RESET "\n", msg);
 	exit(-1);
 }
 
-static void assertFailureAndContinueCallback(const char* msg) {
-	fprintf(stderr, TOY_CC_ASSERT "Assert Failure: %s" TOY_CC_RESET "\n", msg);
+static int assertFailureAndContinueCallback(const char* msg) {
+	return fprintf(stderr, TOY_CC_ASSERT "Assert Failure: %s" TOY_CC_RESET "\n", msg);
 }
 
-static void noOpCallback(const char* msg) {
+static int noOpCallback(const char* msg) {
 	//NO-OP
 	(void)msg;
+	return 0;
 }
 
-static void silentExitCallback(const char* msg) {
+static int silentExitCallback(const char* msg) {
 	//NO-OP
 	(void)msg;
 	exit(-1);
@@ -312,7 +309,7 @@ static void debugScopePrint(Toy_Scope* scope, int depth) {
 //repl function
 int repl(const char* filepath, bool verbose) {
 	//output options
-	Toy_setPrintCallback(printCallback);
+	Toy_setPrintCallback(puts);
 	Toy_setErrorCallback(errorAndContinueCallback);
 	Toy_setAssertFailureCallback(assertFailureAndContinueCallback);
 
@@ -405,7 +402,7 @@ int repl(const char* filepath, bool verbose) {
 
 //main file
 int main(int argc, const char* argv[]) {
-	Toy_setPrintCallback(printCallback);
+	Toy_setPrintCallback(puts);
 	Toy_setErrorCallback(errorAndExitCallback);
 	Toy_setAssertFailureCallback(assertFailureAndExitCallback);
 
diff --git a/source/toy_print.c b/source/toy_print.c
index 4d02d10..5db3cd9 100644
--- a/source/toy_print.c
+++ b/source/toy_print.c
@@ -2,21 +2,9 @@
 
 #include <stdio.h>
 
-static void outDefault(const char* msg) {
-	fprintf(stdout, "%s\n", msg);
-}
-
-static void errDefault(const char* msg) {
-	fprintf(stderr, "%s\n", msg);
-}
-
-static void assertDefault(const char* msg) {
-	fprintf(stderr, "%s\n", msg);
-}
-
-static Toy_callbackType printCallback = outDefault;
-static Toy_callbackType errorCallback = errDefault;
-static Toy_callbackType assertCallback = assertDefault;
+static Toy_callbackType printCallback = puts;
+static Toy_callbackType errorCallback = puts;
+static Toy_callbackType assertCallback = puts;
 
 void Toy_print(const char* msg) {
 	printCallback(msg);
@@ -43,13 +31,13 @@ void Toy_setAssertFailureCallback(Toy_callbackType cb) {
 }
 
 void Toy_resetPrintCallback(void) {
-	printCallback = outDefault;
+	printCallback = puts;
 }
 
 void Toy_resetErrorCallback(void) {
-	errorCallback = errDefault;
+	errorCallback = puts;
 }
 
 void Toy_resetAssertFailureCallback(void) {
-	assertCallback = assertDefault;
+	assertCallback = puts;
 }
diff --git a/source/toy_print.h b/source/toy_print.h
index b358011..313a549 100644
--- a/source/toy_print.h
+++ b/source/toy_print.h
@@ -2,8 +2,8 @@
 
 #include "toy_common.h"
 
-//handle callbacks for printing to the terminal, or elsewhere
-typedef void (*Toy_callbackType)(const char*);
+//handle callbacks for printing to the terminal, or elsewhere (signature matches 'puts')
+typedef int (*Toy_callbackType)(const char*);
 
 TOY_API void Toy_print(const char* msg); //print keyword
 TOY_API void Toy_error(const char* msg); //runtime errors
diff --git a/tests/units/test_print.c b/tests/units/test_print.c
index ccca559..aaae961 100644
--- a/tests/units/test_print.c
+++ b/tests/units/test_print.c
@@ -5,9 +5,10 @@
 
 int counter = 0;
 
-void counterCallback(const char* msg) {
+int counterCallback(const char* msg) {
 	(void)msg;
 	counter++;
+	return 0;
 }
 
 int test_callbacks(void) {
diff --git a/tests/units/test_vm.c b/tests/units/test_vm.c
index bef630c..aa0a545 100644
--- a/tests/units/test_vm.c
+++ b/tests/units/test_vm.c
@@ -161,12 +161,13 @@ int test_opcode_not_equal(Toy_Bucket** bucketHandle) {
 }
 
 static char* callbackUtilReceived = NULL;
-static void callbackUtil(const char* msg) {
+static int callbackUtil(const char* msg) {
 	if (msg != NULL) {
 		free(callbackUtilReceived);
 		callbackUtilReceived = (char*)malloc(strlen(msg) + 1);
 		strcpy(callbackUtilReceived, msg);
 	}
+	return 0;
 }
 
 int test_keyword_assert(Toy_Bucket** bucketHandle) {