Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
I think that system() just passes all its arguments to identify without interpreting ">out.txt" as redirection. You have to do the redirection yourself.
I don't know how you would do this in C++ but in C I did this with the freopen function: