These functions provide an alternative to the C++ stream-based IO classes.
| clearerr | clears errors | 
| fclose | close a file | 
| feof | true if at the end-of-file | 
| ferror | checks for a file error | 
| fflush | writes the contents of the output buffer | 
| fgetc | get a character from a stream | 
| fgetpos | get the file position indicator | 
| fgets | get a string of characters from a stream | 
| fopen | open a file | 
| fprintf | print formatted output to a file | 
| fputc | write a character to a file | 
| fputs | write a string to a file | 
| fread | read from a file | 
| freopen | open an existing stream with a different name | 
| fscanf | read formatted input from a file | 
| fseek | move to a specific location in a file | 
| fsetpos | move to a specific location in a file | 
| ftell | returns the current file position indicator | 
| fwrite | write to a file | 
| getc | read a character from a file | 
| getchar | read a character from stdin | 
| gets | read a string from stdin | 
| perror | displays a string version of the current error to stderr | 
| printf | write formatted output to stdout | 
| putc | write a character to a stream | 
| putchar | write a character to stdout | 
| puts | write a string to stdout | 
| remove | erase a file | 
| rename | rename a file | 
| rewind | move the file position indicator to the beginning of a file | 
| scanf | read formatted input from stdin | 
| setbuf | set the buffer for a specific stream | 
| setvbuf | set the buffer and size for a specific stream | 
| snprintf | write formated output to a buffer (with bound checking) | 
| sprintf | write formatted output to a buffer | 
| sscanf | read formatted input from a buffer | 
| tmpfile | return a pointer to a temporary file | 
| tmpnam | return a unique filename | 
| ungetc | puts a character back into a stream | 
| vprintf, vfprintf, and vsprintf | write formatted output with variable argument lists | 
| vscanf, vfscanf, and vsscanf | gets formatted input from stdin with variable argument lists |