ESP32 Forum

Posted: **Mon Nov 15, 2021 8:25 am**

Hi! I have very strange behaviour of my code. I don't undestand where is the problem.
Here I have vprintf-like function by wich I substitute output of in ESP_LOGe in

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esp_log_set_vprintf(vprintf_like_t_sw_uart_write);

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This is implementation

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int vprintf_like_t_sw_uart_write(const char *format, va_list args)
{
    char buffer[100];
    sprintf(buffer, format, args);
    return sw_uart_write(buffer);
}

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Where sw_uart_write is my own function that create one more software uart (bitbanging).
So if I write e.g.

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arg = 0;
ESP_LOGE("TAG", "esp_loge test %d", arg);

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I see this in my software uart output:

esp_loge test 12

Whatever put instead of arg I always get 12.
What can be wrong?
My sw_uart_write works ok. It's just simple bitbanging.

Posted: **Mon Nov 15, 2021 11:30 am**

UPDATE:
even this function being set as esp_log_set_vprintf(vprintf_like); always transform my args to int 12

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int vprintf_like(const char *format, va_list args)
{
    return printf(format, args);
}

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Posted: **Mon Nov 15, 2021 11:39 am**

Somebody help me.

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esp_log_set_vprintf(printf);

transforms arguments to int 12
usage:

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ESP_LOGE("TAG", "??? main -----------%d",999);

results in printing

??? main -----------12

Posted: **Mon Nov 15, 2021 12:39 pm**

You can't forward the va_list to sprintf. Try vsprintf.

Posted: **Mon Nov 15, 2021 1:31 pm**

boarchuz wrote: ↑
Mon Nov 15, 2021 12:39 pm
You can't forward the va_list to sprintf. Try vsprintf.

Thanks! It works, you are right!

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