Hello! I am having trouble with the '*' specifier in printf, as follows: Serial.begin(9600); char buf[50]; sprintf(buf, "|%-20s|", "HELLO"); Serial.println(buf); I get "|HELLO |" on the serial mon. All good. However, if I try: Serial.begin(9600); char buf[50]; sprintf(buf, "|%-*s|"…

void setup() { char buf[50]; Serial.begin(9600); //print with hard-coded pad length, prints: |HELLO | sprintf(buf, "|%-20s|", "HELLO"); Serial.println(buf); //clear buffer memset(buf, 0, sizeof(buf)); //print with deferred pad length, prints: | sprintf(buf,…

Looks to me that that 'feature' is not supported by the Arduino snprintf, similar to support for floating point. I've tried below few variation as well and the result is the same; both only print the pipe sprintf(buf, "|%*s|", -20, "HELLO"); Serial.println(buf); When printing the buffer byte …

AVR Libc vfprintf() ... Notes: The variable width or precision field (an asterisk * symbol) is not realized and will to abort the output.

Ah. Thanks folks. Looks like we're hardcoding the length :frowning:

You could build the format string on the fly: snprintf(format, sizeof(format), "|%%%ds|", -20); snprintf(buffer, sizeof(buffer), format, "HELLO");

snprintf pad length specifier not working

Projects Programming

UKHeliBob December 31, 2018, 12:18pm 2

Please post a full example program that shows the problem.

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snprintf pad length specifier not working

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