Make examples friendlier for non GCC compilers and fixed slave_mem_i2c.c to compile on boards without I2C pins (#336)

CMakeLists.txt

@@ -28,8 +28,10 @@ add_subdirectory(hello_world)
 add_compile_options(-Wall
         -Wno-format          # int != int32_t as far as the compiler is concerned because gcc has int32_t as long int
         -Wno-unused-function # we have some for the docs that aren't called
-        -Wno-maybe-uninitialized
         )
+if (CMAKE_C_COMPILER_ID STREQUAL "GNU")
+    add_compile_options(-Wno-maybe-uninitialized)
+endif()
 
 # Hardware-specific examples in subdirectories:
 add_subdirectory(adc)

adc/adc_console/adc_console.c

@@ -72,7 +72,7 @@ int main(void) {
                     printf("%03x\n", sample_buf[i]);
                 break;
             }
-            case 'w':
+            case 'w': {
                 printf("\nPress any key to stop wiggling\n");
                 int i = 1;
                 gpio_set_dir_all_bits(-1);
@@ -85,6 +85,7 @@ int main(void) {
                 gpio_set_dir_all_bits(0);
                 printf("Wiggling halted.\n");
                 break;
+            }
             case '\n':
             case '\r':
                 break;

adc/microphone_adc/microphone_adc.c

@@ -44,6 +44,4 @@ int main() {
         printf("%.2f\n", adc_raw * ADC_CONVERT);
         sleep_ms(10);
     }
-
-    return 0;
 }

adc/onboard_temperature/onboard_temperature.c

@@ -58,6 +58,4 @@ int main() {
 #endif
         sleep_ms(990);
     }
-
-    return 0;
 }

flash/cache_perfctr/flash_cache_perfctr.c

@@ -79,7 +79,9 @@ int main() {
     printf("Hit rate so far: %.1f%%\n", hit * 100.f / access);
 
     printf("Calculate 25th fibonacci number: %d\n", recursive_fibonacci(25));
-    printf("New hit rate after printf and fibonacci: %.1f%%\n", xip_ctrl_hw->ctr_hit * 100.f / xip_ctrl_hw->ctr_acc);
+    uint32_t ctr_hit = xip_ctrl_hw->ctr_hit;
+    uint32_t ctr_acc = xip_ctrl_hw->ctr_acc;
+    printf("New hit rate after printf and fibonacci: %.1f%%\n", ctr_hit * 100.f / ctr_acc);
 
     check_hit_miss_invalidate();
 

flash/nuke/nuke.c

@@ -17,7 +17,7 @@
 //
 // To the CMakeLists.txt app for this file. Just to be sure, we can check the
 // define:
-#if !PICO_NO_FLASH
+#if !PICO_NO_FLASH && !PICO_COPY_TO_RAM
 #error "This example must be built to run from SRAM!"
 #endif
 

gpio/hello_7segment/hello_7segment.c

@@ -89,7 +89,5 @@ int main() {
         sleep_ms(250);
         gpio_clr_mask(mask);
     }
-
-    return 0;
 }
 /// \end::hello_gpio[]

gpio/hello_gpio_irq/hello_gpio_irq.c

@@ -27,8 +27,6 @@ int main() {
 
     // Wait forever
     while (1);
-
-    return 0;
 }
 
 

hello_world/serial/hello_serial.c

@@ -13,5 +13,4 @@ int main() {
         printf("Hello, world!\n");
         sleep_ms(1000);
     }
-    return 0;
 }

hello_world/usb/hello_usb.c

@@ -13,5 +13,4 @@ int main() {
         printf("Hello, world!\n");
         sleep_ms(1000);
     }
-    return 0;
 }

i2c/bmp280_i2c/bmp280_i2c.c

@@ -214,6 +214,7 @@ int main() {
 #if !defined(i2c_default) || !defined(PICO_DEFAULT_I2C_SDA_PIN) || !defined(PICO_DEFAULT_I2C_SCL_PIN)
     #warning i2c / bmp280_i2c example requires a board with I2C pins
         puts("Default I2C pins were not defined");
+    return 0;
 #else
     // useful information for picotool
     bi_decl(bi_2pins_with_func(PICO_DEFAULT_I2C_SDA_PIN, PICO_DEFAULT_I2C_SCL_PIN, GPIO_FUNC_I2C));
@@ -248,7 +249,5 @@ int main() {
         // poll every 500ms
         sleep_ms(500);
     }
-
 #endif
-    return 0;
 }

i2c/ht16k33_i2c/ht16k33_i2c.c

@@ -224,7 +224,5 @@ again:
     ht16k33_set_blink(0);
 
     goto again;
-
-    return 0;
 #endif
 }

i2c/lcd_1602_i2c/lcd_1602_i2c.c

@@ -163,7 +163,5 @@ int main() {
             lcd_clear();
         }
     }
-
-    return 0;
 #endif
 }

i2c/lis3dh_i2c/lis3dh_i2c.c

@@ -122,8 +122,7 @@ int main() {
         sleep_ms(500);
 
         // Clear terminal 
-        printf("\e[1;1H\e[2J");
+        printf("\033[1;1H\033[2J");
     }
 #endif
-    return 0;
 }

i2c/mma8451_i2c/mma8451_i2c.c

@@ -121,7 +121,7 @@ int main() {
         sleep_ms(500);
 
         // Clear terminal 
-        printf("\e[1;1H\e[2J");
+        printf("\033[1;1H\033[2J");
     }
 
 #endif

i2c/mpl3115a2_i2c/mpl3115a2_i2c.c

@@ -148,12 +148,15 @@ void mpl3115a2_convert_fifo_batch(uint8_t start, volatile uint8_t buf[], struct
 
     // 3 altitude registers: MSB (8 bits), CSB (8 bits) and LSB (4 bits, starting from MSB)
     // first two are integer bits (2's complement) and LSB is fractional bits -> makes 20 bit signed integer
-    int32_t h = (int32_t) ((uint32_t) buf[start] << 24 | buf[start + 1] << 16 | buf[start + 2] << 8);
+    int32_t h = (int32_t) buf[start] << 24;
+    h |= (int32_t) buf[start + 1] << 16;
+    h |= (int32_t) buf[start + 2] << 8;
     data->altitude = ((float)h) / 65536.f;
 
     // 2 temperature registers: MSB (8 bits) and LSB (4 bits, starting from MSB)
     // first 8 are integer bits with sign and LSB is fractional bits -> 12 bit signed integer
-    int16_t t = (int16_t) (((uint16_t) buf[start + 3]) << 8 | buf[start + 4]);
+    int16_t t = (int16_t) buf[start + 3] << 8;
+    t |= (int16_t) buf[start + 4];
     data->temperature = ((float)t) / 256.f;
 }
 
@@ -162,6 +165,7 @@ int main() {
 #if !defined(i2c_default) || !defined(PICO_DEFAULT_I2C_SDA_PIN) || !defined(PICO_DEFAULT_I2C_SCL_PIN)
 #warning i2c / mpl3115a2_i2c example requires a board with I2C pins
     puts("Default I2C pins were not defined");
+    return 0;
 #else
     printf("Hello, MPL3115A2. Waiting for something to interrupt me!...\n");
 
@@ -202,5 +206,4 @@ int main() {
     };
 
 #endif
-    return 0;
 }

i2c/mpu6050_i2c/mpu6050_i2c.c

@@ -82,6 +82,7 @@ int main() {
 #if !defined(i2c_default) || !defined(PICO_DEFAULT_I2C_SDA_PIN) || !defined(PICO_DEFAULT_I2C_SCL_PIN)
     #warning i2c/mpu6050_i2c example requires a board with I2C pins
     puts("Default I2C pins were not defined");
+    return 0;
 #else
     printf("Hello, MPU6050! Reading raw data from registers...\n");
 
@@ -111,7 +112,5 @@ int main() {
 
         sleep_ms(100);
     }
-
 #endif
-    return 0;
 }

i2c/pa1010d_i2c/pa1010d_i2c.c

@@ -24,7 +24,7 @@
 */
 
 const int addr = 0x10;
-const int max_read = 250;
+#define MAX_READ 250
 
 #ifdef i2c_default
 
@@ -44,24 +44,24 @@ void pa1010d_parse_string(char output[], char protocol[]) {
     int p = com_index - output;
 
     // Splits components of output sentence into array
-    int no_of_fields = 14;
-    int max_len = 15;
+#define NO_OF_FIELDS 14
+#define MAX_LEN 15
 
     int n = 0;
     int m = 0;
 
-    char gps_data[no_of_fields][max_len];
+    char gps_data[NO_OF_FIELDS][MAX_LEN];
     memset(gps_data, 0, sizeof(gps_data));
 
     bool complete = false;
-    while (output[p] != '$' && n < max_len && complete == false) {
+    while (output[p] != '$' && n < MAX_LEN && complete == false) {
         if (output[p] == ',' || output[p] == '*') {
             n += 1;
             m = 0;
         } else {
             gps_data[n][m] = output[p];
             // Checks if sentence is complete
-            if (m < no_of_fields) {
+            if (m < NO_OF_FIELDS) {
                 m++;
             } else {
                 complete = true;
@@ -92,15 +92,15 @@ void pa1010d_parse_string(char output[], char protocol[]) {
 }
 
 void pa1010d_read_raw(char numcommand[]) {
-    uint8_t buffer[max_read];
+    uint8_t buffer[MAX_READ];
 
     int i = 0;
     bool complete = false;
 
-    i2c_read_blocking(i2c_default, addr, buffer, max_read, false);
+    i2c_read_blocking(i2c_default, addr, buffer, MAX_READ, false);
 
     // Convert bytes to characters
-    while (i < max_read && complete == false) {
+    while (i < MAX_READ && complete == false) {
         numcommand[i] = buffer[i];
         // Stop converting at end of message 
         if (buffer[i] == 10 && buffer[i + 1] == 10) {
@@ -119,7 +119,7 @@ int main() {
     puts("Default I2C pins were not defined");
 #else
 
-    char numcommand[max_read];
+    char numcommand[MAX_READ];
 
     // Decide which protocols you would like to retrieve data from
     char init_command[] = "$PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*29\r\n";
@@ -140,7 +140,7 @@ int main() {
 
     while (1) {
         // Clear array
-        memset(numcommand, 0, max_read);
+        memset(numcommand, 0, MAX_READ);
         // Read and re-format
         pa1010d_read_raw(numcommand);
         pa1010d_parse_string(numcommand, "GNRMC");
@@ -149,8 +149,7 @@ int main() {
         sleep_ms(1000);
 
         // Clear terminal 
-        printf("\e[1;1H\e[2J");
+        printf("\033[1;1H\033[2J");
     }
 #endif
-    return 0;
 }

i2c/pcf8523_i2c/pcf8523_i2c.c

@@ -156,9 +156,8 @@ int main() {
         sleep_ms(500);
 
         // Clear terminal 
-        printf("\e[1;1H\e[2J");
+        printf("\033[1;1H\033[2J");
     }
 #endif
-    return 0;
 }
 

i2c/slave_mem_i2c/slave_mem_i2c.c

@@ -14,6 +14,7 @@
 static const uint I2C_SLAVE_ADDRESS = 0x17;
 static const uint I2C_BAUDRATE = 100000; // 100 kHz
 
+#ifdef i2c_default
 // For this example, we run both the master and slave from the same board.
 // You'll need to wire pin GP4 to GP6 (SDA), and pin GP5 to GP7 (SCL).
 static const uint I2C_SLAVE_SDA_PIN = PICO_DEFAULT_I2C_SDA_PIN; // 4
@@ -124,11 +125,18 @@ static void run_master() {
         sleep_ms(2000);
     }
 }
+#endif
 
 int main() {
     stdio_init_all();
+#if !defined(i2c_default) || !defined(PICO_DEFAULT_I2C_SDA_PIN) || !defined(PICO_DEFAULT_I2C_SCL_PIN)
+#warning i2c / slave_mem_i2c example requires a board with I2C pins
+    puts("Default I2C pins were not defined");
+    return 0;
+#else
     puts("\nI2C slave example");
 
     setup_slave();
     run_master();
+#endif
 }

interp/hello_interp/hello_interp.c

@@ -58,8 +58,11 @@ void cross_lanes() {
     interp0->base[0] = 1;
     interp0->base[1] = 0;
     puts("Lane result crossover:");
-    for (int i = 0; i < 10; ++i)
-        printf("PEEK0, POP1: %d, %d\n", interp0->peek[0], interp0->pop[1]);
+    for (int i = 0; i < 10; ++i) {
+        uint32_t peek0 = interp0->peek[0];
+        uint32_t pop1 = interp0->pop[1];
+        printf("PEEK0, POP1: %d, %d\n", peek0, pop1);
+    }
 }
 
 void simple_blend1() {
@@ -107,7 +110,7 @@ void simple_blend2() {
     interp_config_set_blend(&cfg, true);
     interp_set_config(interp0, 0, &cfg);
 
-    interp0->base[0] = -1000;
+    interp0->base[0] = (uint32_t) -1000;
     interp0->base[1] = 1000;
 
     puts("signed:");
@@ -178,8 +181,10 @@ void linear_interpolation() {
         int16_t *sample_pair = (int16_t *) interp0->peek[2];
         interp0->base[0] = sample_pair[0];
         interp0->base[1] = sample_pair[1];
-        printf("%d\t(%d%% between %d and %d)\n", (int) interp0->peek[1],
-               100 * (interp0->add_raw[1] & 0xff) / 0xff,
+        uint32_t peek1 = interp0->peek[1];
+        uint32_t add_raw1 = interp0->add_raw[1];
+        printf("%d\t(%d%% between %d and %d)\n", (int) peek1,
+               100 * (add_raw1 & 0xff) / 0xff,
                sample_pair[0], sample_pair[1]);
         interp0->add_raw[0] = step;
     }

multicore/multicore_runner_queue/multicore_runner_queue.c

@@ -13,7 +13,7 @@
 
 typedef struct
 {
-    void *func;
+    int32_t (*func)(int32_t);
     int32_t data;
 } queue_entry_t;
 
@@ -31,8 +31,7 @@ void core1_entry() {
 
         queue_remove_blocking(&call_queue, &entry);
 
-        int32_t (*func)() = (int32_t(*)())(entry.func);
-        int32_t result = (*func)(entry.data);
+        int32_t result = entry.func(entry.data);
 
         queue_add_blocking(&results_queue, &result);
     }
@@ -78,7 +77,7 @@ int main() {
 
     multicore_launch_core1(core1_entry);
 
-    queue_entry_t entry = {&factorial, TEST_NUM};
+    queue_entry_t entry = {factorial, TEST_NUM};
     queue_add_blocking(&call_queue, &entry);
 
     // We could now do a load of stuff on core 0 and get our result later
@@ -88,7 +87,7 @@ int main() {
     printf("Factorial %d is %d\n", TEST_NUM, res);
 
     // Now try a different function
-    entry.func = &fibonacci;
+    entry.func = fibonacci;
     queue_add_blocking(&call_queue, &entry);
 
     queue_remove_blocking(&results_queue, &res);

pio/apa102/apa102.c

@@ -20,6 +20,10 @@
 // Global brightness value 0->31
 #define BRIGHTNESS 16
 
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
 void put_start_frame(PIO pio, uint sm) {
     pio_sm_put_blocking(pio, sm, 0u);
 }
@@ -50,7 +54,7 @@ int main() {
     apa102_mini_program_init(pio, sm, offset, SERIAL_FREQ, PIN_CLK, PIN_DIN);
 
     for (int i = 0; i < TABLE_SIZE; ++i)
-        wave_table[i] = powf(sinf(i * M_PI / TABLE_SIZE), 5.f) * 255;
+        wave_table[i] = (uint8_t) (powf(sinf(i * M_PI / TABLE_SIZE), 5.f) * 255);
 
     uint t = 0;
     while (true) {

pio/i2c/i2c.pio

@@ -110,8 +110,8 @@ static inline void i2c_program_init(PIO pio, uint sm, uint offset, uint pin_sda,
 
     // Clear IRQ flag before starting, and make sure flag doesn't actually
     // assert a system-level interrupt (we're using it as a status flag)
-    pio_set_irq0_source_enabled(pio, pis_interrupt0 + sm, false);
-    pio_set_irq1_source_enabled(pio, pis_interrupt0 + sm, false);
+    pio_set_irq0_source_enabled(pio, (enum pio_interrupt_source) ((uint) pis_interrupt0 + sm), false);
+    pio_set_irq1_source_enabled(pio, (enum pio_interrupt_source) ((uint) pis_interrupt0 + sm), false);
     pio_interrupt_clear(pio, sm);
 
     // Configure and start SM

pio/i2c/pio_i2c.c

@@ -33,10 +33,14 @@ static inline void pio_i2c_put16(PIO pio, uint sm, uint16_t data) {
     while (pio_sm_is_tx_fifo_full(pio, sm))
         ;
     // some versions of GCC dislike this
+#ifdef __GNUC__
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wstrict-aliasing"
+#endif
     *(io_rw_16 *)&pio->txf[sm] = data;
+#ifdef __GNUC__
 #pragma GCC diagnostic pop
+#endif
 }
 
 
@@ -48,10 +52,14 @@ void pio_i2c_put_or_err(PIO pio, uint sm, uint16_t data) {
     if (pio_i2c_check_error(pio, sm))
         return;
     // some versions of GCC dislike this
+#ifdef __GNUC__
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wstrict-aliasing"
+#endif
     *(io_rw_16 *)&pio->txf[sm] = data;
+#ifdef __GNUC__
 #pragma GCC diagnostic pop
+#endif
 }
 
 uint8_t pio_i2c_get(PIO pio, uint sm) {

pio/st7789_lcd/st7789_lcd.c

@@ -30,6 +30,10 @@
 
 #define SERIAL_CLK_DIV 1.f
 
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
 // Format: cmd length (including cmd byte), post delay in units of 5 ms, then cmd payload
 // Note the delays have been shortened a little
 static const uint8_t st7789_init_seq[] = {
@@ -130,8 +134,8 @@ int main() {
         if (theta > theta_max)
             theta -= theta_max;
         int32_t rotate[4] = {
-                cosf(theta) * (1 << UNIT_LSB), -sinf(theta) * (1 << UNIT_LSB),
-                sinf(theta) * (1 << UNIT_LSB), cosf(theta) * (1 << UNIT_LSB)
+                (int32_t) (cosf(theta) * (1 << UNIT_LSB)), (int32_t) (-sinf(theta) * (1 << UNIT_LSB)),
+                (int32_t) (sinf(theta) * (1 << UNIT_LSB)), (int32_t) (cosf(theta) * (1 << UNIT_LSB))
         };
         interp0->base[0] = rotate[0];
         interp0->base[1] = rotate[2];

pio/ws2812/ws2812_parallel.c

@@ -83,9 +83,9 @@ void pattern_solid(uint len, uint t) {
     }
 }
 
+int level = 8;
 
 void pattern_fade(uint len, uint t) {
-    const int level = 8;
     uint shift = 4;
 
     uint max = 16; // let's not draw too much current!

pwm/measure_duty_cycle/measure_duty_cycle.c

@@ -64,7 +64,7 @@ int main() {
     // values should be very close!
     for (int i = 0; i < count_of(test_duty_cycles); ++i) {
         float output_duty_cycle = test_duty_cycles[i];
-        pwm_set_gpio_level(OUTPUT_PIN, output_duty_cycle * (count_top + 1));
+        pwm_set_gpio_level(OUTPUT_PIN, (uint16_t) (output_duty_cycle * (count_top + 1)));
         float measured_duty_cycle = measure_duty_cycle(MEASURE_PIN);
         printf("Output duty cycle = %.1f%%, measured input duty cycle = %.1f%%\n",
                output_duty_cycle * 100.f, measured_duty_cycle * 100.f);

rtc/hello_rtc/hello_rtc.c

@@ -43,7 +43,5 @@ int main() {
         printf("\r%s      ", datetime_str);
         sleep_ms(100);
     }
-
-    return 0;
 }
 /// \end::hello_rtc_main[]

rtc/rtc_alarm_repeat/rtc_alarm_repeat.c

@@ -56,6 +56,4 @@ int main() {
 
     // Alarm will keep firing forever
     while(1);
-
-    return 0;
 }

spi/bme280_spi/bme280_spi.c

@@ -235,7 +235,5 @@ int main() {
 
         sleep_ms(1000);
     }
-
-    return 0;
 #endif
 }

spi/max7219_32x8_spi/max7219_32x8_spi.c

@@ -135,7 +135,5 @@ int main() {
 
         bright++;
     }
-
-    return 0;
 #endif
 }

spi/max7219_8x7seg_spi/max7219_8x7seg_spi.c

@@ -142,7 +142,5 @@ int main() {
             j = 0;
         }
     }
-
-    return 0;
 #endif
 }

spi/mpu9250_spi/mpu9250_spi.c

@@ -150,6 +150,4 @@ int main() {
 
         sleep_ms(100);
     }
-
-    return 0;
 }

system/narrow_io_write/narrow_io_write.c

@@ -37,8 +37,10 @@ int main() {
     // on transfer size and address LSBs
     printf("\nReading back 1 byte at a time\n");
     // Little-endian!
-    printf("Should be ef be ad de: %02x %02x %02x %02x\n",
-           scratch8[0], scratch8[1], scratch8[2], scratch8[3]);
+    printf("Should be ef be ad de: %02x ", scratch8[0]);
+    printf("%02x ", scratch8[1]);
+    printf("%02x ", scratch8[2]);
+    printf("%02x\n", scratch8[3]);
 
     // The Cortex-M0+ and the RP2040 DMA replicate byte writes across the bus,
     // and IO registers will sample the entire write bus always.

uart/lcd_uart/lcd_uart.c

@@ -151,7 +151,7 @@ int main() {
 #if LCD_IS_RGB
     uint8_t i = 0; // it's ok if this overflows and wraps, we're using sin
     const float frequency = 0.1f;
-    float red, green, blue;
+    uint8_t red, green, blue;
 #endif
 
     while (1) {
@@ -163,9 +163,9 @@ int main() {
         if (c < 128) uart_putc_raw(UART_ID, c); // skip extra non-ASCII chars
 #if LCD_IS_RGB
         // change the display color on keypress, rainbow style!
-        red = sin(frequency * i + 0) * 127 + 128;
-        green = sin(frequency * i + 2) * 127 + 128;
-        blue = sin(frequency * i + 4) * 127 + 128;
+        red = (uint8_t)(sin(frequency * i + 0) * 127 + 128);
+        green = (uint8_t)(sin(frequency * i + 2) * 127 + 128);
+        blue = (uint8_t)(sin(frequency * i + 4) * 127 + 128);
         lcd_set_backlight_color(red, green, blue);
         i++;
 #endif

usb/CMakeLists.txt

@@ -9,8 +9,8 @@ else ()
     message("Skipping TinyUSB host examples as TinyUSB is unavailable")
 endif ()
 if (TARGET tinyusb_pico_pio_usb)
-    if (CMAKE_C_COMPILER_ID STREQUAL "GNU" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 11.3)
-        message("Skipping TinyUSB dual examples, as TinyUSB hw/mcu/raspberry_pi/Pico-PIO-USB does not currently compile on GCC 11.3 or greater")
+    if ((NOT CMAKE_C_COMPILER_ID STREQUAL "GNU") OR CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 11.3)
+        message("Skipping TinyUSB dual examples, as TinyUSB hw/mcu/raspberry_pi/Pico-PIO-USB does not currently compile on non GCC or GCC 11.3 or greater")
     else()
         add_subdirectory(dual)
     endif()

usb/device/dev_hid_composite/main.c

@@ -65,8 +65,6 @@ int main(void)
 
     hid_task();
   }
-
-  return 0;
 }
 
 //--------------------------------------------------------------------+

usb/device/dev_lowlevel/dev_lowlevel.c

@@ -26,8 +26,8 @@
 // Device descriptors
 #include "dev_lowlevel.h"
 
-#define usb_hw_set hw_set_alias(usb_hw)
-#define usb_hw_clear hw_clear_alias(usb_hw)
+#define usb_hw_set ((usb_hw_t *)hw_set_alias_untyped(usb_hw))
+#define usb_hw_clear ((usb_hw_t *)hw_clear_alias_untyped(usb_hw))
 
 // Function prototypes for our device specific endpoint handlers defined
 // later on
@@ -575,6 +575,4 @@ int main(void) {
     while (1) {
         tight_loop_contents();
     }
-
-    return 0;
 }