The C run-time library contains about 400 functions divided into the
categories listed below.
 
Category                   Contents
Buffer manipulation        Manipulate areas of memory on a character basis
Character classification   Test individual characters
Data conversion            Convert numbers to strings and vice versa
Directory control          Manipulate directory structure and information
File handling              Manipulate files
Graphics - fonts           Font manipulation
Graphics - Low-level       Graphics primitives
Graphics - Presentation    Presentation and charting routines
I/O - Streams              Stream I/O routines
I/O - Low-level            Low-level I/O routines
I/O - Console and Port     Console and port I/O routines
Math                       Math routines
Memory allocation          Allocate, free and realloate memory
Process control            Manipulate processes and programs
Searching and sorting      Binary search, linear search and quicksort routines
String manipulation        String functions
System calls - BIOS        BIOS interrupt services
System calls - DOS         DOS interface routines
Time                       Manipulate system time
Variable-length args       Variable-length argument lists
Miscellaneous              Other C functions