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How to compare a string
How to split in stringHow to get string parts from string?How to writte simple string compare?I2C_Anything String / Char Array issuesHow to clear of contents of string in Arduino?How to convert String to Double?WebSocket client for ArduinoHttpClient conditional if with readString() incoming data bufferSending a string to arduino and is not reacting to itHow to compare two string?String compare when using Serial
How to compare a string coming from serial monitor with some predefined text stored as a local variable?
if i say:
int led = 2;
String a = " abcds";
void setup()
Serial.begin(9600);
void loop(){
String b = Serial.read();
Serial.println(b);
if(b != a)
digitalWrite(2,LOW);
else
digitalWrite(2,HIGH);
just as an example, this code will not compile because on the serial i receive bytes and i want to compare with a string.
So my question is...
how should be done?
Thanks in advance !
string
New contributor
add a comment |
How to compare a string coming from serial monitor with some predefined text stored as a local variable?
if i say:
int led = 2;
String a = " abcds";
void setup()
Serial.begin(9600);
void loop(){
String b = Serial.read();
Serial.println(b);
if(b != a)
digitalWrite(2,LOW);
else
digitalWrite(2,HIGH);
just as an example, this code will not compile because on the serial i receive bytes and i want to compare with a string.
So my question is...
how should be done?
Thanks in advance !
string
New contributor
For which arduino board? Most of us try to avoid the String class for the arduino uno. As soon as a character is available, you add it to a buffer or to a String. Sometimes the data from the serial port is closed with a linefeed, then you can process the text in the buffer or in the String when a linefeed is read.
– Jot
4 hours ago
add a comment |
How to compare a string coming from serial monitor with some predefined text stored as a local variable?
if i say:
int led = 2;
String a = " abcds";
void setup()
Serial.begin(9600);
void loop(){
String b = Serial.read();
Serial.println(b);
if(b != a)
digitalWrite(2,LOW);
else
digitalWrite(2,HIGH);
just as an example, this code will not compile because on the serial i receive bytes and i want to compare with a string.
So my question is...
how should be done?
Thanks in advance !
string
New contributor
How to compare a string coming from serial monitor with some predefined text stored as a local variable?
if i say:
int led = 2;
String a = " abcds";
void setup()
Serial.begin(9600);
void loop(){
String b = Serial.read();
Serial.println(b);
if(b != a)
digitalWrite(2,LOW);
else
digitalWrite(2,HIGH);
just as an example, this code will not compile because on the serial i receive bytes and i want to compare with a string.
So my question is...
how should be done?
Thanks in advance !
string
string
New contributor
New contributor
New contributor
asked 6 hours ago
Iulian ChirvasaIulian Chirvasa
82
82
New contributor
New contributor
For which arduino board? Most of us try to avoid the String class for the arduino uno. As soon as a character is available, you add it to a buffer or to a String. Sometimes the data from the serial port is closed with a linefeed, then you can process the text in the buffer or in the String when a linefeed is read.
– Jot
4 hours ago
add a comment |
For which arduino board? Most of us try to avoid the String class for the arduino uno. As soon as a character is available, you add it to a buffer or to a String. Sometimes the data from the serial port is closed with a linefeed, then you can process the text in the buffer or in the String when a linefeed is read.
– Jot
4 hours ago
For which arduino board? Most of us try to avoid the String class for the arduino uno. As soon as a character is available, you add it to a buffer or to a String. Sometimes the data from the serial port is closed with a linefeed, then you can process the text in the buffer or in the String when a linefeed is read.
– Jot
4 hours ago
For which arduino board? Most of us try to avoid the String class for the arduino uno. As soon as a character is available, you add it to a buffer or to a String. Sometimes the data from the serial port is closed with a linefeed, then you can process the text in the buffer or in the String when a linefeed is read.
– Jot
4 hours ago
add a comment |
4 Answers
4
active
oldest
votes
If you do a Google search on "Arduino String" you should find a class reference on the String class. https://www.arduino.cc/reference/en/language/variables/data-types/stringobject/
It has a function compareTo()
that should do what you need.
add a comment |
C has strcmp() function that is used to compare two strings. It will return zero if two strings are equal non zero when not.
New contributor
I started to suggest the same thing, and then noticed that the OP is using Arduino String objects, not C strings.
– Duncan C
4 hours ago
add a comment |
version using String (not recommended)
#define LED 2
const char* a = "abcd";
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
String s = Serial.readStringUntil('n');
s.trim();
if (s == a)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
the version with C-string:
#define LED 2
const char* a = "abcd";
char buffer[32];
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
size_t l = Serial.readBytesUntil('n', buffer, sizeof(buffer - 1));
if (buffer[l - 1] == 'r')
l--;
buffer[l] = 0; // the terminating zero
Serial.println(buffer);
if (strcmp(buffer, a) == 0)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
As I already commented on VE7JRO's post,Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
TheString
version works perfectly, but I can't get theC-string
version to work. For me, the serial monitor shows "abcd" written out to 2 lines: line 1 prints "ab", line 2 prints "cd". Perhaps it's the old version of the IDE I'm using (1.0.6.2). I like that you provided 2 example sketches so the OP can see the difference in compile size:String
4364 bytes VSC-string
2746 bytes.
– VE7JRO
2 hours ago
add a comment |
Here is a test sketch that uses a char
array VS the String
object. Please remember to set the serial monitor to send a newline only.
char inputBuffer[16];
char compareToThisString[] = "test string";
void setup()
Serial.begin(9600);
void loop()
if(Serial.available() > 0)
Serial.readBytesUntil('n', inputBuffer, 16);
if(strcmp(compareToThisString, inputBuffer) == 0)
Serial.println("Matches");
else
Serial.println("No Match");
memset(inputBuffer, 0, sizeof(inputBuffer));
As Egar Bonet mentions in his comments, there is a (up to) one second delay before Serial.readBytesUntil() terminates. That does not apply to the sketch I've written because the function terminates as soon as it receives the n
character. Serial.readBytesUntil()
is blocking code, but that is a different matter which may or may not be an issue for you, depending on what you're building and how much data you are sending. To reduce the timeout period, there is a Serial.setTimeout() function which could be set to whatever you want, but it only comes into play if you don't send the n
character.
why the memset?
– Juraj
3 hours ago
1
read max 15 to have one zero left in the array
– Juraj
3 hours ago
I'm usingmemset()
to "zero out" the input buffer after each use. Withoutmemset()
, if you type in the correct string, it matches. If you then type in just the first 4 letter of the string, it matches which is incorrect. Usingmemset()
only cost an extra 10 bytes compile size.
– VE7JRO
2 hours ago
Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
"read max 15 to have one zero left in the array". I just tried it, and it doesn't work :( Replacingmemset()
with this:inputBuffer[0] = '';
doesn't work either.
– VE7JRO
2 hours ago
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
If you do a Google search on "Arduino String" you should find a class reference on the String class. https://www.arduino.cc/reference/en/language/variables/data-types/stringobject/
It has a function compareTo()
that should do what you need.
add a comment |
If you do a Google search on "Arduino String" you should find a class reference on the String class. https://www.arduino.cc/reference/en/language/variables/data-types/stringobject/
It has a function compareTo()
that should do what you need.
add a comment |
If you do a Google search on "Arduino String" you should find a class reference on the String class. https://www.arduino.cc/reference/en/language/variables/data-types/stringobject/
It has a function compareTo()
that should do what you need.
If you do a Google search on "Arduino String" you should find a class reference on the String class. https://www.arduino.cc/reference/en/language/variables/data-types/stringobject/
It has a function compareTo()
that should do what you need.
answered 5 hours ago
Duncan CDuncan C
1,9701618
1,9701618
add a comment |
add a comment |
C has strcmp() function that is used to compare two strings. It will return zero if two strings are equal non zero when not.
New contributor
I started to suggest the same thing, and then noticed that the OP is using Arduino String objects, not C strings.
– Duncan C
4 hours ago
add a comment |
C has strcmp() function that is used to compare two strings. It will return zero if two strings are equal non zero when not.
New contributor
I started to suggest the same thing, and then noticed that the OP is using Arduino String objects, not C strings.
– Duncan C
4 hours ago
add a comment |
C has strcmp() function that is used to compare two strings. It will return zero if two strings are equal non zero when not.
New contributor
C has strcmp() function that is used to compare two strings. It will return zero if two strings are equal non zero when not.
New contributor
New contributor
answered 4 hours ago
VaibhavVaibhav
592
592
New contributor
New contributor
I started to suggest the same thing, and then noticed that the OP is using Arduino String objects, not C strings.
– Duncan C
4 hours ago
add a comment |
I started to suggest the same thing, and then noticed that the OP is using Arduino String objects, not C strings.
– Duncan C
4 hours ago
I started to suggest the same thing, and then noticed that the OP is using Arduino String objects, not C strings.
– Duncan C
4 hours ago
I started to suggest the same thing, and then noticed that the OP is using Arduino String objects, not C strings.
– Duncan C
4 hours ago
add a comment |
version using String (not recommended)
#define LED 2
const char* a = "abcd";
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
String s = Serial.readStringUntil('n');
s.trim();
if (s == a)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
the version with C-string:
#define LED 2
const char* a = "abcd";
char buffer[32];
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
size_t l = Serial.readBytesUntil('n', buffer, sizeof(buffer - 1));
if (buffer[l - 1] == 'r')
l--;
buffer[l] = 0; // the terminating zero
Serial.println(buffer);
if (strcmp(buffer, a) == 0)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
As I already commented on VE7JRO's post,Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
TheString
version works perfectly, but I can't get theC-string
version to work. For me, the serial monitor shows "abcd" written out to 2 lines: line 1 prints "ab", line 2 prints "cd". Perhaps it's the old version of the IDE I'm using (1.0.6.2). I like that you provided 2 example sketches so the OP can see the difference in compile size:String
4364 bytes VSC-string
2746 bytes.
– VE7JRO
2 hours ago
add a comment |
version using String (not recommended)
#define LED 2
const char* a = "abcd";
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
String s = Serial.readStringUntil('n');
s.trim();
if (s == a)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
the version with C-string:
#define LED 2
const char* a = "abcd";
char buffer[32];
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
size_t l = Serial.readBytesUntil('n', buffer, sizeof(buffer - 1));
if (buffer[l - 1] == 'r')
l--;
buffer[l] = 0; // the terminating zero
Serial.println(buffer);
if (strcmp(buffer, a) == 0)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
As I already commented on VE7JRO's post,Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
TheString
version works perfectly, but I can't get theC-string
version to work. For me, the serial monitor shows "abcd" written out to 2 lines: line 1 prints "ab", line 2 prints "cd". Perhaps it's the old version of the IDE I'm using (1.0.6.2). I like that you provided 2 example sketches so the OP can see the difference in compile size:String
4364 bytes VSC-string
2746 bytes.
– VE7JRO
2 hours ago
add a comment |
version using String (not recommended)
#define LED 2
const char* a = "abcd";
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
String s = Serial.readStringUntil('n');
s.trim();
if (s == a)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
the version with C-string:
#define LED 2
const char* a = "abcd";
char buffer[32];
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
size_t l = Serial.readBytesUntil('n', buffer, sizeof(buffer - 1));
if (buffer[l - 1] == 'r')
l--;
buffer[l] = 0; // the terminating zero
Serial.println(buffer);
if (strcmp(buffer, a) == 0)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
version using String (not recommended)
#define LED 2
const char* a = "abcd";
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
String s = Serial.readStringUntil('n');
s.trim();
if (s == a)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
the version with C-string:
#define LED 2
const char* a = "abcd";
char buffer[32];
void setup()
Serial.begin(115200);
pinMode(LED, OUTPUT);
void loop()
if (Serial.available())
size_t l = Serial.readBytesUntil('n', buffer, sizeof(buffer - 1));
if (buffer[l - 1] == 'r')
l--;
buffer[l] = 0; // the terminating zero
Serial.println(buffer);
if (strcmp(buffer, a) == 0)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
answered 3 hours ago
JurajJuraj
8,19621128
8,19621128
As I already commented on VE7JRO's post,Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
TheString
version works perfectly, but I can't get theC-string
version to work. For me, the serial monitor shows "abcd" written out to 2 lines: line 1 prints "ab", line 2 prints "cd". Perhaps it's the old version of the IDE I'm using (1.0.6.2). I like that you provided 2 example sketches so the OP can see the difference in compile size:String
4364 bytes VSC-string
2746 bytes.
– VE7JRO
2 hours ago
add a comment |
As I already commented on VE7JRO's post,Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
TheString
version works perfectly, but I can't get theC-string
version to work. For me, the serial monitor shows "abcd" written out to 2 lines: line 1 prints "ab", line 2 prints "cd". Perhaps it's the old version of the IDE I'm using (1.0.6.2). I like that you provided 2 example sketches so the OP can see the difference in compile size:String
4364 bytes VSC-string
2746 bytes.
– VE7JRO
2 hours ago
As I already commented on VE7JRO's post,
Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.– Edgar Bonet
2 hours ago
As I already commented on VE7JRO's post,
Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.– Edgar Bonet
2 hours ago
The
String
version works perfectly, but I can't get the C-string
version to work. For me, the serial monitor shows "abcd" written out to 2 lines: line 1 prints "ab", line 2 prints "cd". Perhaps it's the old version of the IDE I'm using (1.0.6.2). I like that you provided 2 example sketches so the OP can see the difference in compile size: String
4364 bytes VS C-string
2746 bytes.– VE7JRO
2 hours ago
The
String
version works perfectly, but I can't get the C-string
version to work. For me, the serial monitor shows "abcd" written out to 2 lines: line 1 prints "ab", line 2 prints "cd". Perhaps it's the old version of the IDE I'm using (1.0.6.2). I like that you provided 2 example sketches so the OP can see the difference in compile size: String
4364 bytes VS C-string
2746 bytes.– VE7JRO
2 hours ago
add a comment |
Here is a test sketch that uses a char
array VS the String
object. Please remember to set the serial monitor to send a newline only.
char inputBuffer[16];
char compareToThisString[] = "test string";
void setup()
Serial.begin(9600);
void loop()
if(Serial.available() > 0)
Serial.readBytesUntil('n', inputBuffer, 16);
if(strcmp(compareToThisString, inputBuffer) == 0)
Serial.println("Matches");
else
Serial.println("No Match");
memset(inputBuffer, 0, sizeof(inputBuffer));
As Egar Bonet mentions in his comments, there is a (up to) one second delay before Serial.readBytesUntil() terminates. That does not apply to the sketch I've written because the function terminates as soon as it receives the n
character. Serial.readBytesUntil()
is blocking code, but that is a different matter which may or may not be an issue for you, depending on what you're building and how much data you are sending. To reduce the timeout period, there is a Serial.setTimeout() function which could be set to whatever you want, but it only comes into play if you don't send the n
character.
why the memset?
– Juraj
3 hours ago
1
read max 15 to have one zero left in the array
– Juraj
3 hours ago
I'm usingmemset()
to "zero out" the input buffer after each use. Withoutmemset()
, if you type in the correct string, it matches. If you then type in just the first 4 letter of the string, it matches which is incorrect. Usingmemset()
only cost an extra 10 bytes compile size.
– VE7JRO
2 hours ago
Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
"read max 15 to have one zero left in the array". I just tried it, and it doesn't work :( Replacingmemset()
with this:inputBuffer[0] = '';
doesn't work either.
– VE7JRO
2 hours ago
add a comment |
Here is a test sketch that uses a char
array VS the String
object. Please remember to set the serial monitor to send a newline only.
char inputBuffer[16];
char compareToThisString[] = "test string";
void setup()
Serial.begin(9600);
void loop()
if(Serial.available() > 0)
Serial.readBytesUntil('n', inputBuffer, 16);
if(strcmp(compareToThisString, inputBuffer) == 0)
Serial.println("Matches");
else
Serial.println("No Match");
memset(inputBuffer, 0, sizeof(inputBuffer));
As Egar Bonet mentions in his comments, there is a (up to) one second delay before Serial.readBytesUntil() terminates. That does not apply to the sketch I've written because the function terminates as soon as it receives the n
character. Serial.readBytesUntil()
is blocking code, but that is a different matter which may or may not be an issue for you, depending on what you're building and how much data you are sending. To reduce the timeout period, there is a Serial.setTimeout() function which could be set to whatever you want, but it only comes into play if you don't send the n
character.
why the memset?
– Juraj
3 hours ago
1
read max 15 to have one zero left in the array
– Juraj
3 hours ago
I'm usingmemset()
to "zero out" the input buffer after each use. Withoutmemset()
, if you type in the correct string, it matches. If you then type in just the first 4 letter of the string, it matches which is incorrect. Usingmemset()
only cost an extra 10 bytes compile size.
– VE7JRO
2 hours ago
Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
"read max 15 to have one zero left in the array". I just tried it, and it doesn't work :( Replacingmemset()
with this:inputBuffer[0] = '';
doesn't work either.
– VE7JRO
2 hours ago
add a comment |
Here is a test sketch that uses a char
array VS the String
object. Please remember to set the serial monitor to send a newline only.
char inputBuffer[16];
char compareToThisString[] = "test string";
void setup()
Serial.begin(9600);
void loop()
if(Serial.available() > 0)
Serial.readBytesUntil('n', inputBuffer, 16);
if(strcmp(compareToThisString, inputBuffer) == 0)
Serial.println("Matches");
else
Serial.println("No Match");
memset(inputBuffer, 0, sizeof(inputBuffer));
As Egar Bonet mentions in his comments, there is a (up to) one second delay before Serial.readBytesUntil() terminates. That does not apply to the sketch I've written because the function terminates as soon as it receives the n
character. Serial.readBytesUntil()
is blocking code, but that is a different matter which may or may not be an issue for you, depending on what you're building and how much data you are sending. To reduce the timeout period, there is a Serial.setTimeout() function which could be set to whatever you want, but it only comes into play if you don't send the n
character.
Here is a test sketch that uses a char
array VS the String
object. Please remember to set the serial monitor to send a newline only.
char inputBuffer[16];
char compareToThisString[] = "test string";
void setup()
Serial.begin(9600);
void loop()
if(Serial.available() > 0)
Serial.readBytesUntil('n', inputBuffer, 16);
if(strcmp(compareToThisString, inputBuffer) == 0)
Serial.println("Matches");
else
Serial.println("No Match");
memset(inputBuffer, 0, sizeof(inputBuffer));
As Egar Bonet mentions in his comments, there is a (up to) one second delay before Serial.readBytesUntil() terminates. That does not apply to the sketch I've written because the function terminates as soon as it receives the n
character. Serial.readBytesUntil()
is blocking code, but that is a different matter which may or may not be an issue for you, depending on what you're building and how much data you are sending. To reduce the timeout period, there is a Serial.setTimeout() function which could be set to whatever you want, but it only comes into play if you don't send the n
character.
edited 2 hours ago
answered 3 hours ago
VE7JROVE7JRO
1,65151122
1,65151122
why the memset?
– Juraj
3 hours ago
1
read max 15 to have one zero left in the array
– Juraj
3 hours ago
I'm usingmemset()
to "zero out" the input buffer after each use. Withoutmemset()
, if you type in the correct string, it matches. If you then type in just the first 4 letter of the string, it matches which is incorrect. Usingmemset()
only cost an extra 10 bytes compile size.
– VE7JRO
2 hours ago
Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
"read max 15 to have one zero left in the array". I just tried it, and it doesn't work :( Replacingmemset()
with this:inputBuffer[0] = '';
doesn't work either.
– VE7JRO
2 hours ago
add a comment |
why the memset?
– Juraj
3 hours ago
1
read max 15 to have one zero left in the array
– Juraj
3 hours ago
I'm usingmemset()
to "zero out" the input buffer after each use. Withoutmemset()
, if you type in the correct string, it matches. If you then type in just the first 4 letter of the string, it matches which is incorrect. Usingmemset()
only cost an extra 10 bytes compile size.
– VE7JRO
2 hours ago
Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.
– Edgar Bonet
2 hours ago
"read max 15 to have one zero left in the array". I just tried it, and it doesn't work :( Replacingmemset()
with this:inputBuffer[0] = '';
doesn't work either.
– VE7JRO
2 hours ago
why the memset?
– Juraj
3 hours ago
why the memset?
– Juraj
3 hours ago
1
1
read max 15 to have one zero left in the array
– Juraj
3 hours ago
read max 15 to have one zero left in the array
– Juraj
3 hours ago
I'm using
memset()
to "zero out" the input buffer after each use. Without memset()
, if you type in the correct string, it matches. If you then type in just the first 4 letter of the string, it matches which is incorrect. Using memset()
only cost an extra 10 bytes compile size.– VE7JRO
2 hours ago
I'm using
memset()
to "zero out" the input buffer after each use. Without memset()
, if you type in the correct string, it matches. If you then type in just the first 4 letter of the string, it matches which is incorrect. Using memset()
only cost an extra 10 bytes compile size.– VE7JRO
2 hours ago
Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.– Edgar Bonet
2 hours ago
Stream::readBytesUntil()
will wait for the terminating character until it gets it or it times out, which can lead to long delays during which the sketch is unresponsive. A better solution is to read only whatever is available, and process the buffer when an LF is read. C.f. the blog post Reading Serial on the Arduino, by Majenko, for a better solution.– Edgar Bonet
2 hours ago
"read max 15 to have one zero left in the array". I just tried it, and it doesn't work :( Replacing
memset()
with this: inputBuffer[0] = '';
doesn't work either.– VE7JRO
2 hours ago
"read max 15 to have one zero left in the array". I just tried it, and it doesn't work :( Replacing
memset()
with this: inputBuffer[0] = '';
doesn't work either.– VE7JRO
2 hours ago
add a comment |
Iulian Chirvasa is a new contributor. Be nice, and check out our Code of Conduct.
Iulian Chirvasa is a new contributor. Be nice, and check out our Code of Conduct.
Iulian Chirvasa is a new contributor. Be nice, and check out our Code of Conduct.
Iulian Chirvasa is a new contributor. Be nice, and check out our Code of Conduct.
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For which arduino board? Most of us try to avoid the String class for the arduino uno. As soon as a character is available, you add it to a buffer or to a String. Sometimes the data from the serial port is closed with a linefeed, then you can process the text in the buffer or in the String when a linefeed is read.
– Jot
4 hours ago