有时 [...] 您会遇到这样的情况,即您希望对要调用的规则施加特定的顺序,而不是在执行这些规则之一时强制更新目标。在这种情况下,您想要定义仅订单的先决条件。可以通过在先决条件列表中放置管道符号 (|) 来指定仅订单先决条件:管道符号左侧的任何先决条件都是正常的;右侧的任何先决条件都是仅订购的:
targets : normal-prerequisites | order-only-prerequisites
仅订单的先决条件不包含在$^
; 您可以使用$|
.
我发现这对于将系统库指定为链接的附加依赖项很有用。
CXX = cl
CXXFLAGS = /nologo /W4 /EHsc /MD
RC = rc
RCFLAGS = /nologo
# Link executables; $^ = all prerequisites; $| = order-only prerequisites
%.exe: %.obj %.res
$(CXX) $(CXXFLAGS) /Fe$@ $^ $|
# Compile source files
%.obj: %.cpp
$(CXX) $(CXXFLAGS) /c /Fo$@ $^
# Compile resource files
%.res: %.rc
$(RC) $(RCFLAGS) /r /fo$@ $^
# System libraries needed for linking. Specify them as order-only prerequisites
# so their (no-op) rule being executed (due to their absence from the build
# directory) won't make the target appear out of date.
ErrorShow.exe: | user32.lib
Singleton.exe: | user32.lib advapi32.lib
ProcessInfo.exe: | user32.lib advapi32.lib gdi32.lib
# Set libraries as no-op targets to satisfy rule existence requirement.
advapi32.lib:
gdi32.lib:
user32.lib:
有没有办法让 Microsoft NMAKE 做同样的事情?