This article was previously published under Q57658
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This article explains how you can set the errorlevel of a program for useby the MS-DOS batch file IF ERRORLEVEL command.
If you are writing a program that is going to be invoked from within anMS-DOS batch file that uses the IF ERRORLEVEL command, you can useInterrupt 21H Function 4CH, "Terminate Process with Return Code" to set theerrorlevel in your program. This function terminates the program andreturns the errorlevel to the parent process, which in this case isCOMMAND.COM running the batch file.
The parameters for Interrupt 21H, Function 4CH are AH = 4CH, AL =errorlevel, followed by a call to Interrupt 21H. The errorlevel can beany value in the range 0 to 255 (0 to FF, hexadecimal).
"Microsoft MS-DOS User's Guide and Reference" for versions 4.x.
"Microsoft MS-DOS Programmer's Reference," version 4.0, Chapter 1,pages 237-238.
"MS-DOS Encyclopedia," Ray Duncan, Microsoft Press, Article 4, pages115-117, and Section V, pages 1375-1376.
"Advanced MS-DOS Programming," Ray Duncan, Microsoft Press, SectionII, pages 443-444.
"The New Peter Norton Programmer's Guide to the IBM PC & PS/2," PeterNorton and Richard Wilton, Microsoft Press, Chapter 17, page 377.