Application development tips

Cross-platform functions

Most POSIX calls are supported on Unix and Windows. For areas that are different (e.g. scanning directories) BOINC supplies some generic functions with implementations for all platforms. Similar code may be available from other open-source projects.

double dtime()

return Unix time with fractional seconds

double dday()

return Unix time at start of this day

void boinc_sleep(double)

sleep for given period

read_file_string(const char*, string)

read file into string

etc. See lib/util.h and lib/filesys.h for others.

Windows-specific issues

• The set of 'standard' DLL differs somewhat among 9X/NT/2000/XP. To avoid crashing because a DLL is missing, call ::LoadLibrary() and then get function pointers.
• Visual Studio: set 'Create/Use? Precompiled Header' to 'Automatically Generate' (/YX) in C/C++ Precompiled Header project properties.
• Visual Studio: change 'Compile As' to 'Compile as C++ Code (/TP)' in C/C++ 'Compile As' project properties.

Unix-specific issues

Shared libraries

Your application can use shared libraries (.so). Include these as separate files. They will reside in your project's directory on the client host. The BOINC client appends the project directory to LD_LIBRARY_PATH, so your program will find them and run correctly.

A problem may arise if you support multiple platforms (say, Linux32 and Linux64). You need different versions of the shared library for each platform. These libraries must have distinct physical names - say, libfoo_1.1_linux32.so and libfoo_1.1_linux64.so.

But what if there are multiple shared libraries, and some depend on others? It may be difficult to change the Makefiles to use distinct names. Here's what you can do to solve this problem:

• Give each shared library a name of the form PHYSICAL=LOGICAL.
• Require client version 6.1.11 or greater. On Unix, these clients create symbolic links from the slot directory to the project directory, and the append the slot directory to LD_LIBRARY_PATH.

Stack size

Several BOINC projects have experienced application crashes that turned out to be stack overflow. This can be fixed by calling:

rlimit rlp;
 
getrlimit(RLIMIT_STACK, &rlp);
rlp.rlim_cur = rlp.rlim_max;
setrlimit(RLIMIT_STACK, &rlp);

before initializing BOINC.

Compression

If you release new versions frequently, have a large executable, and want to conserve server bandwidth, you may want to compress your executable. The best way to do this is with ​Ultimate Packer for eXecutables (UPX).