Linker Errors Encountered while Building dmic

Question

I'm encountering linker errors while attempting to build dmic (PDM mic for data logging) using the Nordic SDK. However, during compilation, I'm facing linker errors related to standard C library functions such as close, read, write, lseek, and open.

Below are the details of my setup and the errors encountered:

This code will write the received audio data to a file named "audio.pcm" in the current directory in PCM format.

#include <stdio.h>
#include <zephyr/kernel.h>
#include <zephyr/audio/dmic.h>
#include <zephyr/logging/log.h>

LOG_MODULE_REGISTER(dmic_sample);

#define MAX_SAMPLE_RATE 16000
#define SAMPLE_BIT_WIDTH 16
#define BYTES_PER_SAMPLE sizeof(int16_t)
/* Milliseconds to wait for a block to be read. */
#define READ_TIMEOUT 1000

/* Size of a block for 100 ms of audio data. */
#define BLOCK_SIZE(_sample_rate, _number_of_channels) \
(BYTES_PER_SAMPLE * (_sample_rate / 10) * _number_of_channels)

/* Driver will allocate blocks from this slab to receive audio data into them.
* Application, after getting a given block from the driver and processing its
* data, needs to free that block.
*/
#define MAX_BLOCK_SIZE BLOCK_SIZE(MAX_SAMPLE_RATE, 2)
#define BLOCK_COUNT 4
K_MEM_SLAB_DEFINE_STATIC(mem_slab, MAX_BLOCK_SIZE, BLOCK_COUNT, 4);

static int do_pdm_transfer(const struct device *dmic_dev,
struct dmic_cfg *cfg,
size_t block_count)
{
int ret;

LOG_INF("PCM output rate: %u, channels: %u",
cfg->streams[0].pcm_rate, cfg->channel.req_num_chan);

ret = dmic_configure(dmic_dev, cfg);
if (ret < 0) {
LOG_ERR("Failed to configure the driver: %d", ret);
return ret;
}

ret = dmic_trigger(dmic_dev, DMIC_TRIGGER_START);
if (ret < 0) {
LOG_ERR("START trigger failed: %d", ret);
return ret;
}

FILE *pcm_file = fopen("audio.pcm", "wb");
if (!pcm_file) {
LOG_ERR("Failed to open PCM file for writing");
return -1;
}

for (int i = 0; i < block_count; ++i) {
void *buffer;
uint32_t size;

ret = dmic_read(dmic_dev, 0, &buffer, &size, READ_TIMEOUT);
if (ret < 0) {
LOG_ERR("%d - read failed: %d", i, ret);
fclose(pcm_file);
return ret;
}

// Write audio data to PCM file
fwrite(buffer, 1, size, pcm_file);

k_mem_slab_free(&mem_slab, buffer);
}

fclose(pcm_file);

ret = dmic_trigger(dmic_dev, DMIC_TRIGGER_STOP);
if (ret < 0) {
LOG_ERR("STOP trigger failed: %d", ret);
return ret;
}

return ret;
}

int main(void)
{
const struct device *const dmic_dev = DEVICE_DT_GET(DT_NODELABEL(dmic_dev));
int ret;

LOG_INF("DMIC sample");

if (!device_is_ready(dmic_dev)) {
LOG_ERR("%s is not ready", dmic_dev->name);
return 0;
}

struct pcm_stream_cfg stream = {
.pcm_width = SAMPLE_BIT_WIDTH,
.mem_slab = &mem_slab,
};
struct dmic_cfg cfg = {
.io = {
.min_pdm_clk_freq = 1000000,
.max_pdm_clk_freq = 3500000,
.min_pdm_clk_dc = 40,
.max_pdm_clk_dc = 60,
},
.streams = &stream,
.channel = {
.req_num_streams = 1,
},

};

cfg.channel.req_num_chan = 1;
cfg.channel.req_chan_map_lo =
dmic_build_channel_map(0, 0, PDM_CHAN_LEFT);
cfg.streams[0].pcm_rate = MAX_SAMPLE_RATE;
cfg.streams[0].block_size =
BLOCK_SIZE(cfg.streams[0].pcm_rate, cfg.channel.req_num_chan);

ret = do_pdm_transfer(dmic_dev, &cfg, 2 * BLOCK_COUNT);
if (ret < 0) {
return 0;
}

cfg.channel.req_num_chan = 2;
cfg.channel.req_chan_map_lo =
dmic_build_channel_map(0, 0, PDM_CHAN_LEFT) |
dmic_build_channel_map(1, 0, PDM_CHAN_RIGHT);
cfg.streams[0].pcm_rate = MAX_SAMPLE_RATE;
cfg.streams[0].block_size =
BLOCK_SIZE(cfg.streams[0].pcm_rate, cfg.channel.req_num_chan);

ret = do_pdm_transfer(dmic_dev, &cfg, 2 * BLOCK_COUNT);
if (ret < 0) {
return 0;
}

LOG_INF("Exiting");
return 0;
}

Error-

s\ANUSHKA\dmic\build\zephyr && D:\ncs\toolchains\c57af46cb7\opt\bin\cmake.exe -E true""

d:/ncs/toolchains/c57af46cb7/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: d:\ncs\toolchains\c57af46cb7\opt\zephyr-sdk\arm-zephyr-eabi\bin\../lib/gcc/../../picolibc/arm-zephyr-eabi/lib/thumb/v8-m.main/nofp\libc.a(libc_tinystdio_fdopen.c.o): in function `fdopen':

fdopen.c:(.text.fdopen+0x20): undefined reference to `close'

d:/ncs/toolchains/c57af46cb7/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: fdopen.c:(.text.fdopen+0xa4): undefined reference to `read'

d:/ncs/toolchains/c57af46cb7/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: fdopen.c:(.text.fdopen+0xa8): undefined reference to `write'

d:/ncs/toolchains/c57af46cb7/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: fdopen.c:(.text.fdopen+0xac): undefined reference to `lseek'

d:/ncs/toolchains/c57af46cb7/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: fdopen.c:(.text.fdopen+0xb0): undefined reference to `close'

d:/ncs/toolchains/c57af46cb7/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd.exe: d:\ncs\toolchains\c57af46cb7\opt\zephyr-sdk\arm-zephyr-eabi\bin\../lib/gcc/../../picolibc/arm-zephyr-eabi/lib/thumb/v8-m.main/nofp\libc.a(libc_tinystdio_fopen.c.o): in function `fopen':

fopen.c:(.text.fopen+0x1e): undefined reference to `open

Host operating system- Windows 11

nRF connect sdk toolchain- v2.5.2

nrf sdk- v2.5.99-dev1

I am using the nRF Connect for VS Code extension.