diff --git a/Makefile b/Makefile
index 66d7bbb..905feaa 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 BASE = malloc_playground first_fit calc_tcache_idx
-V2.23 = fastbin_dup fastbin_dup_consolidate fastbin_dup_consolidate fastbin_dup_into_stack house_of_einherjar house_of_force house_of_gods house_of_lore house_of_mind_fastbin house_of_orange house_of_roman house_of_spirit house_of_storm large_bin_attack mmap_overlapping_chunks overlapping_chunks overlapping_chunks_2 poison_null_byte unsafe_unlink unsorted_bin_attack unsorted_bin_into_stack
-V2.24 = fastbin_dup fastbin_dup_consolidate fastbin_dup_consolidate fastbin_dup_into_stack house_of_einherjar house_of_force house_of_gods house_of_lore house_of_mind_fastbin house_of_roman house_of_spirit house_of_storm large_bin_attack mmap_overlapping_chunks overlapping_chunks overlapping_chunks_2 poison_null_byte unsafe_unlink unsorted_bin_attack unsorted_bin_into_stack
+V2.23 = fastbin_dup fastbin_dup_consolidate fastbin_dup_into_stack house_of_einherjar house_of_force house_of_gods house_of_lore house_of_mind_fastbin house_of_orange house_of_roman house_of_spirit house_of_storm large_bin_attack mmap_overlapping_chunks overlapping_chunks overlapping_chunks_2 poison_null_byte unsafe_unlink unsorted_bin_attack unsorted_bin_into_stack
+V2.24 = fastbin_dup fastbin_dup_consolidate fastbin_dup_into_stack house_of_einherjar house_of_force house_of_gods house_of_lore house_of_mind_fastbin house_of_roman house_of_spirit house_of_storm large_bin_attack mmap_overlapping_chunks overlapping_chunks overlapping_chunks_2 poison_null_byte unsafe_unlink unsorted_bin_attack unsorted_bin_into_stack
 V2.27 = fastbin_dup fastbin_dup_consolidate fastbin_dup_into_stack fastbin_reverse_into_tcache house_of_botcake house_of_einherjar house_of_force house_of_lore house_of_mind_fastbin house_of_spirit house_of_storm large_bin_attack mmap_overlapping_chunks overlapping_chunks poison_null_byte tcache_house_of_spirit tcache_poisoning tcache_stashing_unlink_attack unsafe_unlink unsorted_bin_attack unsorted_bin_into_stack
 V2.31 = fastbin_dup fastbin_dup_consolidate fastbin_dup_into_stack fastbin_reverse_into_tcache house_of_botcake house_of_einherjar house_of_lore house_of_mind_fastbin house_of_spirit large_bin_attack mmap_overlapping_chunks overlapping_chunks poison_null_byte tcache_house_of_spirit tcache_poisoning tcache_stashing_unlink_attack unsafe_unlink
 V2.32 = decrypt_safe_linking fastbin_dup fastbin_dup_consolidate fastbin_dup_into_stack fastbin_reverse_into_tcache house_of_botcake house_of_einherjar house_of_lore house_of_mind_fastbin house_of_spirit large_bin_attack mmap_overlapping_chunks overlapping_chunks poison_null_byte tcache_house_of_spirit tcache_poisoning tcache_stashing_unlink_attack unsafe_unlink safe_link_double_protect house_of_water
diff --git a/glibc_2.23/fastbin_dup_consolidate.c b/glibc_2.23/fastbin_dup_consolidate.c
index 30049d0..35c491f 100644
--- a/glibc_2.23/fastbin_dup_consolidate.c
+++ b/glibc_2.23/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -31,4 +31,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }
diff --git a/glibc_2.27/fastbin_dup_consolidate.c b/glibc_2.27/fastbin_dup_consolidate.c
index f632aa5..35af2b0 100644
--- a/glibc_2.27/fastbin_dup_consolidate.c
+++ b/glibc_2.27/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -38,4 +38,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }
diff --git a/glibc_2.31/fastbin_dup_consolidate.c b/glibc_2.31/fastbin_dup_consolidate.c
index f632aa5..35af2b0 100644
--- a/glibc_2.31/fastbin_dup_consolidate.c
+++ b/glibc_2.31/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -38,4 +38,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }
diff --git a/glibc_2.32/fastbin_dup_consolidate.c b/glibc_2.32/fastbin_dup_consolidate.c
index f632aa5..35af2b0 100644
--- a/glibc_2.32/fastbin_dup_consolidate.c
+++ b/glibc_2.32/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -38,4 +38,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }
diff --git a/glibc_2.33/fastbin_dup_consolidate.c b/glibc_2.33/fastbin_dup_consolidate.c
index f632aa5..35af2b0 100644
--- a/glibc_2.33/fastbin_dup_consolidate.c
+++ b/glibc_2.33/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -38,4 +38,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }
diff --git a/glibc_2.34/fastbin_dup_consolidate.c b/glibc_2.34/fastbin_dup_consolidate.c
index f632aa5..35af2b0 100644
--- a/glibc_2.34/fastbin_dup_consolidate.c
+++ b/glibc_2.34/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -38,4 +38,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }
diff --git a/glibc_2.35/fastbin_dup_consolidate.c b/glibc_2.35/fastbin_dup_consolidate.c
index f632aa5..35af2b0 100644
--- a/glibc_2.35/fastbin_dup_consolidate.c
+++ b/glibc_2.35/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -38,4 +38,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }
diff --git a/glibc_2.36/fastbin_dup_consolidate.c b/glibc_2.36/fastbin_dup_consolidate.c
index f632aa5..35af2b0 100644
--- a/glibc_2.36/fastbin_dup_consolidate.c
+++ b/glibc_2.36/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -38,4 +38,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }
diff --git a/glibc_2.37/fastbin_dup_consolidate.c b/glibc_2.37/fastbin_dup_consolidate.c
index f632aa5..35af2b0 100644
--- a/glibc_2.37/fastbin_dup_consolidate.c
+++ b/glibc_2.37/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -38,4 +38,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }
diff --git a/glibc_2.38/fastbin_dup_consolidate.c b/glibc_2.38/fastbin_dup_consolidate.c
index f632aa5..35af2b0 100644
--- a/glibc_2.38/fastbin_dup_consolidate.c
+++ b/glibc_2.38/fastbin_dup_consolidate.c
@@ -2,7 +2,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
-void main() {
+int main() {
 	// reference: https://valsamaras.medium.com/the-toddlers-introduction-to-heap-exploitation-fastbin-dup-consolidate-part-4-2-ce6d68136aa8
 	puts("This is a powerful technique that bypasses the double free check in tcachebin.");
 	printf("Fill up the tcache list to force the fastbin usage...\n");
@@ -38,4 +38,6 @@ void main() {
 	printf("The double free added the chunk referenced by p1 \n");
 	printf("to the tcache thus the next similar-size malloc will\n");
 	printf("point to p3: p3=%p, p4=%p\n\n",p3, p4);
+
+	return 0;
 }