When running examples on windows using "-o" parameter, the path to the output directory should use double slashes, however on the website the examples are given with a single slash (I treid the one from the doxygen:
http://plantuml.sourceforge.net/doxygen.html). Here is the difference between two cases (note that no meaningful error is shown in the first case, which is very confusing):
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c:\Scratch\_project>java -jar c:\Scratch\_different\\plantuml.jar -v -o "c:\Scratch\" .\mainPageDocumentation.h
(0.000 - 0.000 - 0.000(0) - 245 Mo) 243 Mo - PlantUML Version 8009
(0.026 - 0.000 - 0.000(0) - 245 Mo) 243 Mo - GraphicsEnvironment.isHeadless() false
c:\Scratch\_project>java -jar c:\Scratch\_different\\plantuml.jar -v -o "c:\\Scratch\\" .\mainPageDocumentation.h
(0.000 - 0.000 - 0.000(0) - 245 Mo) 243 Mo - PlantUML Version 8009
(0.025 - 0.000 - 0.000(0) - 245 Mo) 243 Mo - GraphicsEnvironment.isHeadless() false
(0.030 - 0.000 - 0.000(0) - 245 Mo) 243 Mo - Setting current dir: .
(0.031 - 0.000 - 0.000(0) - 245 Mo) 243 Mo - Setting current dir: c:\Scratch\_project\programs\VeinPM\src\.
(0.031 - 0.000 - 0.000(0) - 245 Mo) 243 Mo - Using default charset
(0.035 - 0.000 - 0.000(0) - 245 Mo) 242 Mo - Setting current dir: c:\Scratch\_project\programs\VeinPM\src\.
(0.045 - 0.000 - 0.000(0) - 245 Mo) 242 Mo - Setting current dir: c:\Scratch\_project\programs\VeinPM\src\.
(0.045 - 0.000 - 0.000(0) - 245 Mo) 242 Mo - Reading file: .\mainPageDocumentation.h
(0.397 - 0.000 - 0.000(0) - 245 Mo) 224 Mo - Creating file: c:\Scratch\out.png
(0.425 - 0.000 - 0.000(0) - 245 Mo) 221 Mo - Creating image 113x175
(0.494 - 0.000 - 0.000(0) - 245 Mo) 219 Mo - File size : 2568
(0.495 - 0.000 - 0.000(0) - 245 Mo) 219 Mo - Number of image(s): 1
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It would be great if "plantuml.jar" would understand even single slashed, or at least produce a proper error. The documentation on the website is somewhat misleading otherwise.