Finding current executable’s path without /proc/self/exe

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Some OS-specific interfaces:

  • Mac OS X: _NSGetExecutablePath() (man 3 dyld)
  • Linux: readlink /proc/self/exe
  • Solaris: getexecname()
  • FreeBSD: sysctl CTL_KERN KERN_PROC KERN_PROC_PATHNAME -1
  • FreeBSD if it has procfs: readlink /proc/curproc/file (FreeBSD doesn’t have procfs by default)
  • NetBSD: readlink /proc/curproc/exe
  • DragonFly BSD: readlink /proc/curproc/file
  • Windows: GetModuleFileName() with hModule = NULL

There 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 use getenv("_") 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.

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