Determining the OS

We want to identify the OS efficiently and correctly, and there are probably a hundred different ways to do it. First, we’ll try to determine the OS by reading environment variables. If all else fails, we’ll run uname. Create os.mk in the nospb/mk directory.

os.mk

# Try to determine OS name without shelling out to uname if possible.
ifndef __uname
  export __uname:=$(OSNAME)
endif
ifndef __uname
  export __uname:=$(OSTYPE)
endif
ifndef __uname
  # Assume we're running MinGW if not Cygwin.
  export __uname:=$(if $(COMSPEC),mingw,)
endif
ifndef __uname
  # Ran out of environment tricks, so just run uname.
  export __uname:=$(shell uname)
endif

ifeq ($(__uname),cygwin)
  PLATFORM_CYGWIN=1
  ISWINDOWS=1
endif
ifeq ($(__uname),mingw)
  PLATFORM_MINGW=1
  ISWINDOWS=1
endif
ifeq ($(__uname),Darwin)
  PLATFORM_DARWIN=1
  ISBSD=1
  ISUNIX=1
endif
ifeq ($(__uname),FreeBSD)
  PLATFORM_FREEBSD=1
  ISBSD=1
  ISUNIX=1
endif
ifeq ($(__uname),Linux)
  PLATFORM_LINUX=1
  ISUNIX=1
endif

Update rules.mk

Now you need to add os.mk to your rules framework. After the line that defines __nospb_dir, include os.mk.

os.mk snippet

# Include OS identification module.
include $(__nospb_dir)os.mk

NOSPB