| Character and string I/O functions | |
| getchar | Read a character from standard input |
| gets | Read a string from standard input |
| putchar | Write a character to standard output |
| puts | Write a string to standard output |
| Formatted output functions | |
| printf | Write formatted text to standard output |
| snprintf | Write formatted text to a string with truncation |
| sprintf | Write formatted text to a string |
| vprintf | Write formatted text to standard output using variable argument context |
| vsnprintf | Write formatted text to a string with truncation using variable argument context |
| vsprintf | Write formatted text to a string using variable argument context |
| Formatted input functions | |
| scanf | Read formatted text from standard input |
| sscanf | Read formatted text from string |
| vscanf | Read formatted text from standard using variable argument context |
| vsscanf | Read formatted text from a string using variable argument context |