Inference Rule May Fail When Spaces on Blank Command Line

MS-DOS                                  | OS/2

The information in this article applies to:

• Microsoft NMAKE Utility for MS-DOS, versions 1.01, 1.1, 1.11, 1.12, 1.13, 1.2, 1.3, 1.4
• Microsoft NMAKE Utility for OS/2, versions 1.01, 1.11, 1.12, 1.21 ---------------------------------------------------------------------

SUMMARY

When using inference rules in an NMAKE description file, the target/dependency line must be followed by a blank line (no space characters); otherwise, the inference rule commands will not be executed. NMAKE checks this line for any ASCII characters; if ANY characters exist, NMAKE will ignore the inference rule and try to execute the line, even if it contains only a space or spaces.

The following is a simple example, which demonstrates this problem:

.c.exe:

  cl $**

main.exe : main.c <space>

Nothing happens if this description file is passed to NMAKE because the space character causes NMAKE to assume there are explicit commands following the target/dependency line, causing it to ignore the inference rule. Note that this is expected behavior for NMAKE.

MORE INFORMATION

MAKE version 4.x inference rules/description blocks do not exhibit this behavior. This is something to keep in mind when converting description files from MAKE to NMAKE.