It seems to me that Linux has it easy with /proc/self/exe. But I'd like to know if there is a convenient way to find the current application's directory in C/C++ with cross-platform interfaces. I've seen some projects mucking around with argv[0], but it doesn't seem entirely reliable.
If you ever had to support, say, Mac OS X, which doesn't have /proc/, what would you have done? Use #ifdefs to isolate the platform-specific code (NSBundle, for example)? Or try to deduce the executable's path from argv[0], $PATH and whatnot, risking finding bugs in edge cases?
Best Answer
Some OS-specific interfaces:
_NSGetExecutablePath()(man 3 dyld)readlink /proc/self/exegetexecname()sysctl CTL_KERN KERN_PROC KERN_PROC_PATHNAME -1readlink /proc/curproc/file(FreeBSD doesn't have procfs by default)readlink /proc/curproc/exereadlink /proc/curproc/fileGetModuleFileName()withhModule=NULLThere are also third party libraries that can be used to get this information, such as whereami as mentioned in prideout's answer, or if you are using Qt, QCoreApplication::applicationFilePath() as mentioned in the comments.
The portable (but less reliable) method is to use
argv[0]. Although it could be set to anything by the calling program, by convention it is set to either a path name of the executable or a name that was found using$PATH.Some shells, including bash and ksh, set the environment variable "
_" to the full path of the executable before it is executed. In that case you can usegetenv("_")to get it. However this is unreliable because not all shells do this, and it could be set to anything or be left over from a parent process which did not change it before executing your program.