Does opening a file in append mode to write in c++ allocates memory for whole file? -

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does opening file in append mode write in c++ allocates memory whole file?

say have file, opened in append mode , after final append file 34 gb. if file write operation frequent , done different tasks, opens file every time append data it. before final write(when size of file 30 gb) os allocate 30 gb opening file?

short answer: no. opening file, in mode, not allocate memory whole file. may have confused memory-mapping file, can , does.


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