diff --git a/docs/README.md b/docs/README.md
index 4880df5c..9867c1f7 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -204,7 +204,7 @@ option during build time, use the `-D OPTION` compiler flag:
 $ cc app0.c mongoose.c                                        # Use defaults!
 $ cc app1.c mongoose.c -D MG_ENABLE_IPV6=1                    # Build with IPv6 enabled
 $ cc app2.c mongoose.c -D MG_ARCH=MG_ARCH_FREERTOS_LWIP       # Set architecture
-$ cc app3.c mongoose.c -D MG_ENABLE_FS=0 -D MG_ENABLE_LOG=0   # Multiple options
+$ cc app3.c mongoose.c -D MG_ENABLE_STDIO=0 -D MG_ENABLE_LOG=0   # Multiple options
 ```
 
 The list of supported
@@ -237,7 +237,7 @@ Here is a list of build constants and their default values:
 |MG_ENABLE_SOCKET | 1 | Use BSD socket low-level API |
 |MG_ENABLE_MBEDTLS | 0 | Enable Mbed TLS library |
 |MG_ENABLE_OPENSSL | 0 | Enable OpenSSL library |
-|MG_ENABLE_FS | 1 | Enable API that use filesystem, like `mg_http_send_file()` |
+|MG_ENABLE_STDIO | 1 | Enable API that use filesystem, like `mg_http_send_file()` |
 |MG_ENABLE_IPV6 | 0 | Enable IPv6 |
 |MG_ENABLE_LOG | 1 | Enable `LOG()` macro |
 |MG_ENABLE_MD5 | 0 | Use native MD5 implementation |
diff --git a/examples/stm32-freertos-tcp/Makefile b/examples/stm32-freertos-tcp/Makefile
index 8486b2a5..93060089 100644
--- a/examples/stm32-freertos-tcp/Makefile
+++ b/examples/stm32-freertos-tcp/Makefile
@@ -6,7 +6,7 @@ DOCKER ?= docker run -it --rm -v $(PROJECT_ROOT_PATH):$(PROJECT_ROOT_PATH) -w $(
 FREERTOS_KERNEL_PATH ?= $(PROJECT_ROOT_PATH)/test/freertos-kernel
 FREERTOS_PLUS_TCP_PATH ?= $(PROJECT_ROOT_PATH)/test/freertos-tcp
 
-MONGOOSE_FLAGS = -DMG_ARCH=MG_ARCH_FREERTOS_TCP -DMG_ENABLE_FS=1
+MONGOOSE_FLAGS = -DMG_ARCH=MG_ARCH_FREERTOS_TCP -DMG_ENABLE_STDIO=1
 MCU_FLAGS = -mcpu=cortex-m7 -mthumb -mfloat-abi=softfp -mfpu=vfpv4 
 #-mcpu=cortex-m7 -mthumb -mfpu=fpv5-sp-d16 -mfloat-abi=hard
 
diff --git a/examples/stm32-freertos-tcp/main.c b/examples/stm32-freertos-tcp/main.c
index b17e1cf6..2dc99034 100644
--- a/examples/stm32-freertos-tcp/main.c
+++ b/examples/stm32-freertos-tcp/main.c
@@ -10,7 +10,7 @@ static const char *s_listening_address = "http://0.0.0.0:80";
 // Event handler for the listening connection.
 static void cb(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
   if (ev == MG_EV_HTTP_MSG) {
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
     struct mg_http_serve_opts opts = {.root_dir = "/"};
     mg_http_serve_dir(c, ev_data, &opts);
 #else
@@ -99,32 +99,33 @@ uint32_t HAL_GetTick(void) {
 
 #include "stm32f7xx_hal_conf.h"
 #include "stm32fxx_hal_eth.h"
-void HAL_ETH_MspInit( ETH_HandleTypeDef* heth ) {
-    GPIO_InitTypeDef GPIO_InitStructure;
-    if (heth->Instance == ETH) {
-        __HAL_RCC_GPIOA_CLK_ENABLE();
-        __HAL_RCC_GPIOC_CLK_ENABLE();
-        __HAL_RCC_GPIOG_CLK_ENABLE();
+void HAL_ETH_MspInit(ETH_HandleTypeDef *heth) {
+  GPIO_InitTypeDef GPIO_InitStructure;
+  if (heth->Instance == ETH) {
+    __HAL_RCC_GPIOA_CLK_ENABLE();
+    __HAL_RCC_GPIOC_CLK_ENABLE();
+    __HAL_RCC_GPIOG_CLK_ENABLE();
 
-        GPIO_InitStructure.Speed = GPIO_SPEED_HIGH;
-        GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
-        GPIO_InitStructure.Pull = GPIO_NOPULL; 
-        GPIO_InitStructure.Alternate = GPIO_AF11_ETH;
-        GPIO_InitStructure.Pin = GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_7;
-        HAL_GPIO_Init(GPIOA, &GPIO_InitStructure);
+    GPIO_InitStructure.Speed = GPIO_SPEED_HIGH;
+    GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
+    GPIO_InitStructure.Pull = GPIO_NOPULL;
+    GPIO_InitStructure.Alternate = GPIO_AF11_ETH;
+    GPIO_InitStructure.Pin = GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_7;
+    HAL_GPIO_Init(GPIOA, &GPIO_InitStructure);
 
-        GPIO_InitStructure.Pin = GPIO_PIN_1 | GPIO_PIN_4 | GPIO_PIN_5;
-        HAL_GPIO_Init(GPIOC, &GPIO_InitStructure);
+    GPIO_InitStructure.Pin = GPIO_PIN_1 | GPIO_PIN_4 | GPIO_PIN_5;
+    HAL_GPIO_Init(GPIOC, &GPIO_InitStructure);
 
-        GPIO_InitStructure.Pin =  GPIO_PIN_2 | GPIO_PIN_11 | GPIO_PIN_13 | GPIO_PIN_14;
-        HAL_GPIO_Init(GPIOG, &GPIO_InitStructure);
+    GPIO_InitStructure.Pin =
+        GPIO_PIN_2 | GPIO_PIN_11 | GPIO_PIN_13 | GPIO_PIN_14;
+    HAL_GPIO_Init(GPIOG, &GPIO_InitStructure);
 
-        HAL_NVIC_SetPriority(ETH_IRQn, 0x7, 0);
-        HAL_NVIC_EnableIRQ(ETH_IRQn);
-        
-        __HAL_RCC_ETH_CLK_ENABLE();
-        HAL_NVIC_SetPriorityGrouping( NVIC_PRIORITYGROUP_4 );
-    }
+    HAL_NVIC_SetPriority(ETH_IRQn, 0x7, 0);
+    HAL_NVIC_EnableIRQ(ETH_IRQn);
+
+    __HAL_RCC_ETH_CLK_ENABLE();
+    HAL_NVIC_SetPriorityGrouping(NVIC_PRIORITYGROUP_4);
+  }
 }
 
 int vLoggingPrintf(const char *fmt, ...) {
diff --git a/mongoose.c b/mongoose.c
index 873090cd..96ac19ef 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -775,7 +775,7 @@ void mg_http_reply(struct mg_connection *c, int code, const char *headers,
   if (buf != mem) free(buf);
 }
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 static void http_cb(struct mg_connection *, int, void *, void *);
 static void restore_http_cb(struct mg_connection *c) {
   if (c->pfn_data != NULL) fclose((FILE *) c->pfn_data);
@@ -3910,7 +3910,7 @@ struct mg_str mg_url_pass(const char *url) {
 
 
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 int mg_stat(const char *path, mg_stat_t *st) {
 #ifdef _WIN32
   wchar_t tmp[MG_PATH_MAX];
@@ -3982,7 +3982,7 @@ bool mg_file_printf(const char *path, const char *fmt, ...) {
   if (buf != tmp) free(buf);
   return result;
 }
-#endif  // MG_ENABLE_FS
+#endif  // MG_ENABLE_STDIO
 
 void mg_random(void *buf, size_t len) {
   bool done = false;
@@ -3990,14 +3990,14 @@ void mg_random(void *buf, size_t len) {
 #if MG_ARCH == MG_ARCH_ESP32
   while (len--) *p++ = (unsigned char) (esp_random() & 255);
 #elif MG_ARCH == MG_ARCH_WIN32
-#elif MG_ARCH_UNIX && MG_ENABLE_FS
+#elif MG_ARCH_UNIX && MG_ENABLE_STDIO
   FILE *fp = fopen("/dev/urandom", "rb");
   if (fp != NULL) {
     if (fread(buf, 1, len, fp) == len) done = true;
     fclose(fp);
   }
 #endif
-    // Fallback to a pseudo random gen
+  // Fallback to a pseudo random gen
   if (!done) {
     while (len--) *p++ = (unsigned char) (rand() & 255);
   }
@@ -4094,9 +4094,10 @@ char *mg_hex(const void *buf, size_t len, char *to) {
 }
 
 static unsigned char mg_unhex_nimble(unsigned char c) {
-  return (c >= '0' && c <= '9')   ? (unsigned char) (c - '0')
-         : (c >= 'A' && c <= 'F') ? (unsigned char) (c - '7')
-                                  : (unsigned char) (c - 'W');
+  return (c >= '0' && c <= '9')
+             ? (unsigned char) (c - '0')
+             : (c >= 'A' && c <= 'F') ? (unsigned char) (c - '7')
+                                      : (unsigned char) (c - 'W');
 }
 
 unsigned long mg_unhexn(const char *s, size_t len) {
diff --git a/mongoose.h b/mongoose.h
index 86072a4c..ba03763e 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -141,7 +141,7 @@ struct timeval {
 };
 #endif
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 #include <sys/stat.h>
 #endif
 
@@ -181,7 +181,7 @@ static inline void *mg_calloc(int cnt, size_t size) {
 #include <string.h>
 #include <time.h>
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 #include <sys/stat.h>
 #endif
 
@@ -407,8 +407,8 @@ static __inline struct tm *localtime_r(time_t *t, struct tm *tm) {
 #define MG_ENABLE_OPENSSL 0
 #endif
 
-#ifndef MG_ENABLE_FS
-#define MG_ENABLE_FS 1
+#ifndef MG_ENABLE_STDIO
+#define MG_ENABLE_STDIO 1
 #endif
 
 #ifndef MG_ENABLE_SSI
@@ -561,7 +561,7 @@ double mg_time(void);
 unsigned long mg_millis(void);
 void mg_usleep(unsigned long usecs);
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 #ifdef _WIN32
 typedef struct _stati64 mg_stat_t;
 #else
diff --git a/src/arch_freertos_lwip.h b/src/arch_freertos_lwip.h
index 0c60d295..53cdc740 100644
--- a/src/arch_freertos_lwip.h
+++ b/src/arch_freertos_lwip.h
@@ -17,7 +17,7 @@ struct timeval {
 };
 #endif
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 #include <sys/stat.h>
 #endif
 
diff --git a/src/arch_freertos_tcp.h b/src/arch_freertos_tcp.h
index fd76e111..29932732 100644
--- a/src/arch_freertos_tcp.h
+++ b/src/arch_freertos_tcp.h
@@ -13,7 +13,7 @@
 #include <string.h>
 #include <time.h>
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 #include <sys/stat.h>
 #endif
 
diff --git a/src/config.h b/src/config.h
index 86030697..cf40c5fd 100644
--- a/src/config.h
+++ b/src/config.h
@@ -12,8 +12,8 @@
 #define MG_ENABLE_OPENSSL 0
 #endif
 
-#ifndef MG_ENABLE_FS
-#define MG_ENABLE_FS 1
+#ifndef MG_ENABLE_STDIO
+#define MG_ENABLE_STDIO 1
 #endif
 
 #ifndef MG_ENABLE_SSI
diff --git a/src/http.c b/src/http.c
index 2f045971..689871fc 100644
--- a/src/http.c
+++ b/src/http.c
@@ -364,7 +364,7 @@ void mg_http_reply(struct mg_connection *c, int code, const char *headers,
   if (buf != mem) free(buf);
 }
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 static void http_cb(struct mg_connection *, int, void *, void *);
 static void restore_http_cb(struct mg_connection *c) {
   if (c->pfn_data != NULL) fclose((FILE *) c->pfn_data);
diff --git a/src/util.c b/src/util.c
index 2fe80de9..54fb4a4e 100644
--- a/src/util.c
+++ b/src/util.c
@@ -2,7 +2,7 @@
 
 #include "util.h"
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 int mg_stat(const char *path, mg_stat_t *st) {
 #ifdef _WIN32
   wchar_t tmp[MG_PATH_MAX];
@@ -74,7 +74,7 @@ bool mg_file_printf(const char *path, const char *fmt, ...) {
   if (buf != tmp) free(buf);
   return result;
 }
-#endif  // MG_ENABLE_FS
+#endif  // MG_ENABLE_STDIO
 
 void mg_random(void *buf, size_t len) {
   bool done = false;
@@ -82,14 +82,14 @@ void mg_random(void *buf, size_t len) {
 #if MG_ARCH == MG_ARCH_ESP32
   while (len--) *p++ = (unsigned char) (esp_random() & 255);
 #elif MG_ARCH == MG_ARCH_WIN32
-#elif MG_ARCH_UNIX && MG_ENABLE_FS
+#elif MG_ARCH_UNIX && MG_ENABLE_STDIO
   FILE *fp = fopen("/dev/urandom", "rb");
   if (fp != NULL) {
     if (fread(buf, 1, len, fp) == len) done = true;
     fclose(fp);
   }
 #endif
-    // Fallback to a pseudo random gen
+  // Fallback to a pseudo random gen
   if (!done) {
     while (len--) *p++ = (unsigned char) (rand() & 255);
   }
@@ -186,9 +186,10 @@ char *mg_hex(const void *buf, size_t len, char *to) {
 }
 
 static unsigned char mg_unhex_nimble(unsigned char c) {
-  return (c >= '0' && c <= '9')   ? (unsigned char) (c - '0')
-         : (c >= 'A' && c <= 'F') ? (unsigned char) (c - '7')
-                                  : (unsigned char) (c - 'W');
+  return (c >= '0' && c <= '9')
+             ? (unsigned char) (c - '0')
+             : (c >= 'A' && c <= 'F') ? (unsigned char) (c - '7')
+                                      : (unsigned char) (c - 'W');
 }
 
 unsigned long mg_unhexn(const char *s, size_t len) {
diff --git a/src/util.h b/src/util.h
index b436310c..f530f74d 100644
--- a/src/util.h
+++ b/src/util.h
@@ -37,7 +37,7 @@ double mg_time(void);
 unsigned long mg_millis(void);
 void mg_usleep(unsigned long usecs);
 
-#if MG_ENABLE_FS
+#if MG_ENABLE_STDIO
 #ifdef _WIN32
 typedef struct _stati64 mg_stat_t;
 #else