{Solved} PROGMEM variable and conditional compilation

Projects Programming
1

Greetings,

I am trying to put my HTML code for an ESP8266/Arduino webpage in PROGMEM like this

const char INDEX_HTML[] PROGMEM = R"=====(
<!DOCTYPE HTML lang="en-US">
<html>
  <head>
</head>
<body>
  <h1>Captive Portal Main Page</h1> 


</body>
</html>
)=====";

on top of that i am trying to use condional compilation like this

#define TESTBUTTON  
#ifdef TESTBUTTON
   // some code here
#endif

i am trying to use the conditional compilation in the webpage like this

const char INDEX_HTML[] PROGMEM = R"=====(
<!DOCTYPE HTML lang="en-US">
<html>
  <head>
</head>
<body>
  <h1>Captive Portal Main Page</h1> 


#ifdef TESTBUTTON
  <h2>test</h2>
#endif
</body>
</html>
)=====";

i show the webpage like this

String s = INDEX_HTML;
server.send(200, "text/html", s);

however, when compiling with TESTBUTTON not defined (commented out) the

test

still appears.

I am sure it is my (lack of) understanding of PROGMEM that is causing the issue.

If someone knows how to do this, let me know, please

thanks for your time,

Rob

2

Preprocessing directives do not work inside string literals.
However, you can split the literal into parts; multiple adjacent string literals are combined into one.
For example

"foo"
   "bar"

becomes

"foobar"

const char INDEX_HTML[] PROGMEM = R"=====(
<!DOCTYPE HTML lang="en-US">
<html>
  <head>
</head>
<body>
  <h1>Captive Portal Main Page</h1> 


)====="

#ifdef TESTBUTTON
  "<h2>test</h2>\n"
#endif

  R"=====(
</body>
</html>
)=====";
3

look at the page source code in the browser. is there #ifdef TESTBUTTON ?

4

@oqibidipo, You are the man!!!!! that worked for me. Thanks a million.

@Juraj, yes, it did show.