CrossWorks for ARM User Guide

The behaviour of va_start and va_arg is undefined if the parameter parmN is declaredwith the register storage class, with a function or array type, or with a type that is notcompatible with the type that results after application of the default argumentpromotions.va_start must be invoked before any access to the unnamed arguments.va_start and va_copy must not be be invoked to reinitialize ap without an interveninginvocation of the va_end macro for the same ap.Portabilityva_start conforms to ISO/IEC 9899:1990 (C90) and ISO/IEC 9899:1999 (C99).See also va_arg (page 278), va_copy (page 279), va_end (page 279) - Input/output functionsThe header file defines a number of functions to format and output values.The format-control directives that for the formatted input and output function aredescribed in Formatted input control strings (page 285) and Formatted output controlstrings (page 281).Character and string I/O functionsgetchargetsputcharputsRead a character from standard inputRead a string from standard inputWrite a character to standard outputWrite a string to standard outputFormatted input functionsscanfsscanfvscanfvsscanfRead formatted text from standard inputRead formatted text from a stringRead formatted text from standard input using a va_listargumentRead formatted text from a string using a va_list argumentFormatted output functionsprintfsnprintfsprintfWrite formatted text to standard outputWrite formatted text to a string with truncationWrite formatted text to a string280 Chapter 28 Standard C Library Reference