HOWTO: Modify the Environment for a Spawned Process

 Last reviewed: August 26, 1997
Article ID: Q11997

The information in this article applies to:
  • The C Run-time (CRT) included with: - Microsoft C for MS-DOS, versions 6.0, 6.0a, 6.0ax - Microsoft C for OS/2, versions 5.1, 6.0, 6.0a - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versions 1.0, 1.5 - Microsoft Visual C++ 32-bit Edition, versions 1.0, 2.0, 4.0, 5.0

SUMMARY

The text below discusses the process through which an application can modify the PROMPT environment variable in a spawned process. Use the same procedure to modify any environment variable in a spawned process.

PROMPT is an environment variable used by MS-DOS, OS/2, and Windows NT. To change the value for the PROMPT environment variable, use one of the following two methods to specify the environment in which a child process runs.

  • Use one of the spawn*e() functions. See the run-time library reference manual or the online help file provided with your compiler for specific information about the spawn() family of functions.
  • Use the putenv() function to modify the environment in which your application executes, then start the child process with one of the spawn() functions. See the run-time library reference manual or the online help file provided with your compiler for specific information about the putenv() function.

In general, a process can alter only the environment in which a child process will run. The C run-time library functions simulate the ability to alter the environment space in which the current process runs by making a copy of the environment when the process starts up and allowing the process to modify the copy of the environment. 
Keywords          : CRTIss
Version           : MS-DOS:6.0,6.00a,6.00ax,7.0; OS/2:5.1,6.0,6.00a;  WINDOWS:1.0,1.5; WINDOWS NT:1.0,2.0,4.0,5.0
Platform          : MS-DOS NT OS/2 WINDOWS
Issue type        : kbhowto

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Last reviewed: August 26, 1997
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