Add build instructions for linux

[shrx]

Ideally 32 and 64 bit variants

[schnaader]

Related: https://encode.ru/threads/2885-Paq8px-building-instructions

[L3P3]

On Ubuntu 19, if I git clone and enter the given g++ command, beside a few warnings, I get errors like these:

/usr/bin/ld: /tmp/ccitcPAu.o: in function `BmpFilter::encode(File*, File*, unsigned long, int, int&)':
paq8px.cpp:(.text+0x540): undefined reference to `Shared::getInstance()'
/usr/bin/ld: /tmp/ccitcPAu.o: in function `Array<char, 16>::~Array()':
paq8px.cpp:(.text+0x898): undefined reference to `ProgramChecker::free(unsigned long)'
/usr/bin/ld: /tmp/ccitcPAu.o: in function `directEncodeBlock(BlockType, File*, unsigned long, Encoder&, int)':
paq8px.cpp:(.text+0x97c): undefined reference to `Encoder::compress(int)'
/usr/bin/ld: paq8px.cpp:(.text+0x987): undefined reference to `Encoder::encodeBlockSize(unsigned long)'
/usr/bin/ld: paq8px.cpp:(.text+0x999): undefined reference to `Encoder::compress(int)'

[andrew-epstein]

Can you try the following?

cmake .
make

[L3P3]

paq8px/model/Info.cpp: In member function ‘void Info::predict(uint8_t)’:
paq8px/model/Info.cpp:412:9: error: ‘isalpha’ was not declared in this scope
     if( isalpha(c1) != 0 ) {
         ^~~~~~~
paq8px/model/Info.cpp:414:16: error: ‘ispunct’ was not declared in this scope
     } else if( ispunct(c1) != 0 ) {
                ^~~~~~~
paq8px/model/Info.cpp:416:16: error: ‘isspace’ was not declared in this scope
     } else if( isspace(c1) != 0 ) {
                ^~~~~~~
make[2]: *** [CMakeFiles/paq8px.dir/build.make:947: CMakeFiles/paq8px.dir/model/Info.cpp.o] Fehler 1
make[1]: *** [CMakeFiles/Makefile2:73: CMakeFiles/paq8px.dir/all] Error 2
make: *** [Makefile:84: all] Error 2

[andrew-epstein]

@L3P3: Can you try adding #include <cctype> to the top of Info.hpp, along with the other lines that begin with #include? If that fixes the problem, then I'll make sure to include a fix for this issue in the next version.

[L3P3]

Yes, that did it.

[L3P3]

And also update the README with that cmake and make commands...

[andrew-epstein]

And also update the README with that cmake and make commands...

Yes, of course, will do.

[moisespr123]

Updated the README to include newer instructions with cmake and make.

[GotthardtZ]

I believe this issue may be closed.