使用fwrite C ++将压缩数据写入文件

Question

I have a buffer of size 42131221 bytes (42.1MB) that I used to store some compressed data. Only the first 20MB actually store the compressed data and I am trying to write this to a file using fwrite:

fwrite (buffer , WHAT_GOES_HERE, buffer_length, pFile);

The second parameter requires the size of each element to write, but this isn't applicable in this case as I just want to write the whole buffer and since it's compressed, it isn't the case that there exists a size of each element.

Any idea on how I can get this to work?

Answer 1

WHAT_GOES_HERE should be sizeof(type of the buffer). Also, the buffer_length should be the number of "types" you want to write to the file. I mention this since it seems you do not want to write the entire buffer but only the for 20MB.

Answer 2

fwrite works on streams, which are buffered.

write is a lower-level API based on file descriptors. It doesn't know about buffering.

Rule of thumb is,

If you want to write a single large buffer, go for write. You use fwrite if you want to write in smaller chunks.

so, you could go for write here.