"undefined reference" errors while using tidy library, especially "tidy.h" - c

Question

I'm currently using a script which validates an invalid XML file or string using tidy library.
A sample code to test it's running:
#include <tidy.h>
#include <tidybuffio.h>
#include <stdio.h>
#include <errno.h>
int main(int argc, char **argv )
{
const char* input = "<title>Foo</title><p>Foo!";
TidyBuffer output = {0};
TidyBuffer errbuf = {0};
int rc = -1;
Bool ok;
TidyDoc tdoc = tidyCreate(); // Initialize "document"
printf( "Tidying:\t%s\n", input );
ok = tidyOptSetBool( tdoc, TidyXhtmlOut, yes ); // Convert to XHTML
if ( ok )
rc = tidySetErrorBuffer( tdoc, &errbuf ); // Capture diagnostics
if ( rc >= 0 )
rc = tidyParseString( tdoc, input ); // Parse the input
if ( rc >= 0 )
rc = tidyCleanAndRepair( tdoc ); // Tidy it up!
if ( rc >= 0 )
rc = tidyRunDiagnostics( tdoc ); // Kvetch
if ( rc > 1 ) // If error, force output.
rc = ( tidyOptSetBool(tdoc, TidyForceOutput, yes) ? rc : -1 );
if ( rc >= 0 )
rc = tidySaveBuffer( tdoc, &output ); // Pretty Print
if ( rc >= 0 )
{
if ( rc > 0 )
printf( "\nDiagnostics:\n\n%s", errbuf.bp );
printf( "\nAnd here is the result:\n\n%s", output.bp );
}
else
printf( "A severe error (%d) occurred.\n", rc );
tidyBufFree( &output );
tidyBufFree( &errbuf );
tidyRelease( tdoc );
return rc;
}
on running
gcc -I/usr/include/tidy tidy_example.c
I get this output on my terminal:
/tmp/cclFfP4I.o: In function main':
tidy_exa.c:(.text+0x6e): undefined reference totidyCreate'
tidy_exa.c:(.text+0x9e): undefined reference to tidyOptSetBool'
tidy_exa.c:(.text+0xba): undefined reference totidySetErrorBuffer'
tidy_exa.c:(.text+0xd6): undefined reference to tidyParseString'
tidy_exa.c:(.text+0xeb): undefined reference totidyCleanAndRepair'
tidy_exa.c:(.text+0x100): undefined reference to tidyRunDiagnostics'
tidy_exa.c:(.text+0x11f): undefined reference totidyOptSetBool'
tidy_exa.c:(.text+0x149): undefined reference to tidySaveBuffer'
tidy_exa.c:(.text+0x1a6): undefined reference totidyBufFree'
tidy_exa.c:(.text+0x1b2): undefined reference to tidyBufFree'
tidy_exa.c:(.text+0x1be): undefined reference totidyRelease'
collect2: error: ld returned 1 exit status
Any Idea as to how to resolve this issue, or any other library to do the same thing on a file or a string (invalid XML) in c/c++.
Any suggestions will also be welcomed.

Answer 1

You forgot to link the lib using -l option.
For example
gcc -I/usr/include/tidy -ltidy tidy_example.c -o example
If you also need to specify a specific folder for libs you must add -L option like
gcc -I/usr/include/tidy -L/usr/local/lib/tidy -ltidy tidy_example.c -o example