Conventions used

Throughout the manual standard typographic conventions have been used, representing computer code fragments with a fixed width font, whilst equations and equation variables appear in italic type. Where several possibilities exist for the library functions, those with C syntax have been used, and C style conventions have been used for structures such as arrays etc. Where appropriate, the following have also been employed:

• square brackets [...] contain optional material;
• curly brackets {...} contain optional material, of which one must be chosen;
• entities in italics which appear in expressions stand for meta-variables. The description following the meta-variable describes how it is to be used;
• the vertical bar symbol | is found on many keyboards as a vertical line with a small gap in the middle, but often confusingly displays on screen without the small gap in the middle. In UNIX it is referred to as the pipe symbol. Note that this symbol is not the same as the character sometimes used to draw boxes on a PC screen. In ASCII, the | symbol is 7C in hexadecimal, 124 decimal.