在Linux中将库与AC程序链接的问题

Question

I want to run serial commands from a Bealgebone to a 4Dsystems display. Therefore I copied the c library found here into a directory and created a test program main.c:

#include "Picaso_const4D.h" 
#include "Picaso_Serial_4DLibrary.h"

int main(int argc,char *argv[])
{
    OpenComm("/dev/ttyUSB0", B115200);  // Matches with the display "Comms" rate
    gfx_BGcolour(0xFFFF);
    gfx_Cls();
    gfx_CircleFilled(120,160,80,BLUE);
    while (1) {}
}

Now when I do gcc -o main main.c its says

main.c:2:37: fatal error: Picaso_Serial_4DLibrary.h: No such file or directory

So I try linking it:

gcc main.c  -L. -lPICASO_SERIAL_4DLIBRARY

which gives me the same error. Then I tried to create a static library:

gcc -Wall -g -c -o PICASO_SERIAL_4DLIBRARY PICASO_SERIAL_4DLIBRARY.C

which gives me this:

PICASO_SERIAL_4DLIBRARY.C:1:21: fatal error: windows.h: No such file or directory compilation terminated.

What am I doing wrong? the git page clearly says this library is created for people who do not run windows.

Thanks in advance!

Answer 1

You're not getting a linker error; you're getting a preprocessor error. Specifically, your preprocessor can't find Picaso_Serial_4DLibrary.h. Make sure that it's in your include path; you can add directories to your include path using the -I argument to gcc.

Answer 2

You've had two problems. First was the picaso_whatever.h file that couldn't be found. You fixed that with the -I you added. But, now, the picaso.h wants windows.h

What are you building on? WinX or BSD/Linux?

If you're compiling on WinX, you need to install the "platform sdk" for visual studio.

If you're using mingw or cygwin, you need to do something else.

If on WinX, cd to the C: directory. Do find . -type f -name windows.h find . -type f -name windows.h and add a -I for the containing directory.

If under Linux, repeat the find at the source tree top level. Otherwise, there is probably some compatibility cross-build library that you need to install.

Or, you'll have to find WinX that has it as Picaso clearly includes it. You could try commenting out one or more of the #include's for it and see if things are better or worse.

If you can't find a real one, create an empty windows.h and add -I to it and see how bad [or good] things are.

You may need the mingw cross-compiler. See https://forums.wxwidgets.org/viewtopic.php?t=7729

UPDATE:

Okay ... Wow ... You are on the right track and close, but this is, IMO, ugly WinX stuff.

The primary need of Picaso is getting a serial comm port connection, so the need from within windows.h is [thankfully] minimal. It needs basic boilerplate definitions for WORD, DWORD, etc.

mingw or cygwin will provide their own copies of windows.h. These are "clean room" reimplementations, so no copyright issues.

mingw is a collection of compile/build tools that let you use gcc/ld/make build utilities.

cygwin is more like: I'd like a complete shell-like environment similar to BSD/Linux. You get bash, ls, gcc, tar, and just about any GNU utility you want.

Caveat: I use cygwin, but have never used mingw. The mingw version of windows.h [and a suite of .h files that it includes underneath], being open source, can be reused by other projects (eg cygwin, wine).

Under Linux, wine (windows emulator) is a program/suite that attempts to allow you to run WinX binaries under Linux (eg wine mywinpgm).

I git cloned the Picaso library and after some fiddling, I was able to get it to compile after pointing it to wine's version of windows.h

Picaso's OpenComm is doing CreateFile [a win32 API call]. So, you'll probably need cygwin. You're opening /dev/ttyUSB0. /dev/* implies cygwin. But, /dev/ttyUSB0 is a Linux-like name. You may need some WinX-style name like "COM:" or whatever. Under the cygwin terminal [which gives you a bash prompt], do ls /dev and see what's available.

You can get cygwin from: http://cygwin.com/ If you have a 64 bit system, be sure to use the 64 bit version of the installer: setup-x86_64.exe It's semi-graphical and will want two directories, one for the "root" FS and one to store packages. On my system, I use C:\\cygwin64 and C:\\cygwin64_packages--YMMV.

Note that the installer won't install gcc by default. You can [graphically] select which packages to install. You may also need some "devel" packages. They have libraries and .h files that a non-developer wouldn't need. As, docs mention, you can rerun the installer as often as you need. You can add packages that you forgot to specify or even remove ones that you installed that you don't need anymore.

Remember that you'll need to adjust makefile -I and/or -L option appropriately. Also, when building the picaso library, gcc generated a ton of warnings about overflow of a "large integer". The code was doing:

#define control_code -279
unsigned char buf[2];
buf[0] = control_code >> 8;
buf[1] = control_code;

The code is okay, and the warning is correct [because the code is sloppy]. If the code had done:

#define control_code -279
unsigned char buf[2];
buf[0] = (unsigned) control_code >> 8;
buf[1] = (unsigned) control_code;

it probably would have been silent. Use -Wno-overflow in your Makefile to get rid of the warnings rather that edit 50 or so lines