From: Jim Burgess Date: 2010-12-05T21:13:30+09:00 Subject: Re: How to tell if ruby app is already running Hi, Thanks very much for the replies. I tried to install the posixlock gem, but got the following error message: C:/Ruby187/bin/ruby.exe extconf.rb creating Makefile make gcc -I. -I/C/Ruby187/lib/ruby/1.8/i386-mingw32 -I/C/Ruby187/lib/ruby/1.8/i386-mingw32 -I. -g -O2 -DFD_SETSIZE=256 -c posixlock.c posixlock.c:2:26: missing/file.h: No such file or directory posixlock.c: In function `posixlock': posixlock.c:82: error: storage size of 'lock' isn't known posixlock.c:87: error: `F_RDLCK' undeclared (first use in this function) posixlock.c:87: error: (Each undeclared identifier is reported only once posixlock.c:87: error: for each function it appears in.) posixlock.c:90: error: `F_WRLCK' undeclared (first use in this function) posixlock.c:93: error: `F_UNLCK' undeclared (first use in this function) posixlock.c:101: error: `F_SETLK' undeclared (first use in this function) posixlock.c:101: error: `F_SETLKW' undeclared (first use in this function) posixlock.c: In function `rb_file_lockf': posixlock.c:160: error: storage size of 'lock' isn't known posixlock.c:183: error: `F_WRLCK' undeclared (first use in this function) posixlock.c:184: error: `F_SETLKW' undeclared (first use in this function) posixlock.c:187: error: `F_RDLCK' undeclared (first use in this function) posixlock.c:192: error: `F_SETLK' undeclared (first use in this function) posixlock.c:199: error: `F_UNLCK' undeclared (first use in this function) posixlock.c:205: error: `F_GETLK' undeclared (first use in this function) make.exe: *** [posixlock.o] Error 1 I spent ages googling for a solution, but came up empty handed. I then tried implementing Phillip's suggestion and that achieved exactly what I had hoped. Thanks again. -- Posted via http://www.ruby-forum.com/.