wat system commands that can be used for c++?

ive searched google, but cant find any.

you know, like: system("pause");

i would like a whole list if possible, but one in particular im looking for right now is one that will open a file and continue running the program while the file is opened. is there such a command? or another way of doing this? because all i know of right now is: system("filename"); and that waits till you close the file to continue on with the program.
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~Jawn
Diamond FC: 0817-5204-5224

I propose writing C programs without using any flow control statements (if/switch/while/do/for/goto), only allowing the main function, variable definitions, the standard library, and the use of operators. No semicolons after the last defined variable either. This is a Touring-complete system for application development: there's the comma operator for evaluating several expressions, ?: for conditions, and system for recursivity/control flow.