Functions

 Functions consist of one or more blocks of statements that perform
 one logical operation.  They can be called from other functions
 either in the same program or in different programs.  A function
 may exchange values with the calling function by use of parameters.

 Function declarations have the following syntax:

      function_name()
 or
      function_name(arg1, arg2,...)
 or
      function_name(data-type arg1, data-type arg2,...)

 In the first form of the function declaration, the function takes
 no arguments.  In the second form, the function takes arguments;
 the arguments are declared outside the parameter list.  In the
 third form, the function declaration is a function prototype that
 specifies the type of its arguments in the identifier list; the
 prototype form is recommended.  In all three cases, the parenthesis
 after the function name are required.

 VSI C for OpenVMS Systems provides a library of common functions.
 These functions perform standard I/O operations, character and
 string handling, mathematical operations, miscellaneous system
 services, and UNIX* system emulation.  For more information, see
 HELP CRTL.



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* UNIX is a trademark of The Open Group.