Typographical conventions
The following table explains the typographical conventions used in this document.
Typeface | Indicates | Example |
---|---|---|
bold | Commands, executable names, compiler options and pragma directives | If you specify -O3, the compiler assumes -qhot=level=0. To prevent all HOT optimizations with -O3, you must specify -qnohot. |
italics | Parameters or variables whose actual names or values are to be supplied by the user. Italics are also used to introduce new terms | The maximum length of the trigger_constant in fixed source form is 4 for directives that are continued on one or more lines. |
monospace | Examples of program code, command strings, or user-defined names | Also, specify the following
runtime options before running the program, with a command similar to the
following: export XLFRTEOPTS="err_recovery=no:
langlvl=90std" |
Syntax diagrams
Throughout this document, diagrams illustrate XL Fortran syntax. This section will help you to interpret and use those diagrams.
The >>--- symbol indicates the beginning of a command, directive, or statement.
The ---> symbol indicates that the command, directive, or statement syntax is continued on the next line.
The >--- symbol indicates that a command, directive, or statement is continued from the previous line.
The --->< symbol indicates the end of a command, directive, or statement.
Fragments, which are diagrams of syntactical units other than complete commands, directives, or statements, start with the |--- symbol and end with the ---| symbol.
IBM XL Fortran extensions are marked by a number in the syntax diagram with an explanatory note immediately following the diagram.
Program units, procedures, constructs, interface blocks and derived-type definitions consist of several individual statements. For such items, a box encloses the syntax representation, and individual syntax diagrams show the required order for the equivalent Fortran statements.
>>-keyword--required_argument----------------------------------><
>>-keyword--+-------------------+------------------------------>< '-optional_argument-'
If you must choose one of the items, one item of the stack is shown on the main path.
>>-keyword--+-required_argument1-+----------------------------->< '-required_argument2-'
If choosing one of the items is optional, the entire stack is shown below the main path.
>>-keyword--+--------------------+----------------------------->< +-optional_argument1-+ '-optional_argument2-'
.-,-------------------. V | >>-keyword----repeatable_argument-+----------------------------><
.-default_argument---. >>-keyword--+-alternate_argument-+-----------------------------><
Sample syntax diagram
The following is an example of a syntax diagram with an interpretation:
.-,-. (1) V | >>-EXAMPLE-------char_constant--+-a-+--+---+----e-+-------------> '-b-' +-c-+ '-d-' >--name_list---------------------------------------------------><
Interpret the diagram as follows: