27 lines
1.0 KiB
Markdown
27 lines
1.0 KiB
Markdown
# Chapter 3 – Buffered I/O
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## Difference Between Byte-Level and Buffered I/O
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- **System calls** like `read()` and `write()` operate at a low level: each call may result in direct disk access.
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- **C libraries** use buffered I/O (`fread()`, `fwrite()`, `fprintf()`), accumulating data in memory to reduce system calls.
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## Buffered I/O API
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- Uses `FILE *` type from `<stdio.h>`.
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- Functions:
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- `fopen()`, `fclose()`: open/close file.
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- `fread()`, `fwrite()`: binary I/O.
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- `fprintf()`, `fscanf()`, `fgets()`, `fputs()`: formatted or text I/O.
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## Types of Buffering
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- **Fully buffered**: flush when buffer is full.
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- **Line buffered**: flush at end of line (e.g., terminals).
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- **Unbuffered**: no accumulation (e.g., stderr).
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## Buffer Management
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- `setvbuf()` or `setbuf()` allows custom buffering.
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- Useful for optimizing performance or interactive environments.
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## When to Use Buffered I/O
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- When performance matters and immediate file system synchronization isn't required.
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- For formatted I/O, the C library offers more simplicity and readability.
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