Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

                                             ◄Up► ◄Contents► ◄Index► ◄Back►
─────NMAKE──────────────────────────────────────────────────────────────────
 
     NMAKE inherits macro definitions for every environment variable
     that existed before the NMAKE session. If a variable was set in
     the operating-system environment, a macro exists that has the same
     name and value. Inheritance occurs before preprocessing.
 
     Environment-variable macro names are in uppercase.
 
     WARNING: If an environment variable contains a dollar sign
              ($), NMAKE interprets it as the beginning of a macro
              invocation. The resulting macro expansion can cause
              unexpected behavior and possibly an error.
 
     Environment-variable macros can be redefined. However, the
     following restrictions apply:
 
        ■ Changing a macro does not change the equivalent environment
          variable. To change the variable, use a SET command.
 
        ■ Changing an environment variable in an NMAKE session using
          the SET command does not change the corresponding macro; to
          change the macro, use a macro definition.
 
     If an environment variable has not been set, there is no
     equivalent macro, and the variable cannot be set using a macro
     definition. However, you can use a SET command in the NMAKE
     session to set the variable. The variable is then in effect for
     the rest of the NMAKE session unless redefined or cleared by a
     later SET command. A SET definition in a makefile does not create
     a corresponding macro; if you want a macro for an environment
     variable that is created during an NMAKE session, you must
     explicitly define the macro in addition to setting the variable.
 
     The /E option causes macros inherited from environment variables
     to override any macros with the same name in the makefile.
     See: ◄/E Option►
          ◄Precedence Among Macro Definitions►
 
     Environment-variable macros are inherited during recursion.
     See: ◄Inherited Macros►
 
     The !INCLUDE preprocessing directive uses the INCLUDE macro, which
     is initially set to the value of the INCLUDE environment variable.
     See: ◄!INCLUDE Directive►
 
     Example
 
          LIB = c:\tools\lib
 
          sample.exe : sample.obj
            LINK sample;
 
     This makefile redefines the environment-variable macro called LIB.
     No matter what value the variable LIB had before, it has the value
     c:\tools\lib when NMAKE executes the specified LINK command.
     Redefining the inherited macro does not affect the original
     environment variable; when NMAKE terminates, LIB still has its
     original value.
 
     However, if LIB is not defined before the NMAKE session, the LIB
     macro definition does not set a LIB environment variable for the
     LINK command. To do this, use the following makefile:
 
          sample.exe : sample.obj
           SET LIB=c:\tools.lib
           LINK sample;
                                    -♦-