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vprintf(3) Library Functions Manual vprintf(3) NAME vprintf, vfprintf, vsprintf - Format a variable number of parameters for output LIBRARY Standard C Library (libc.so, libc.a) SYNOPSIS #include <stdarg.h> #include <stdio.h> int vprintf( const char *format, va_list printarg); int vfprintf( FILE *stream, const char *format, va_list printarg); int vsprintf( char *string, const char *format, va_list printarg); STANDARDS Interfaces documented on this reference page conform to industry stan- dards as follows: vfprintf(), vprintf(), vsprintf(): ISO C, XPG4, XPG4-UNIX Refer to the standards(5) reference page for more information about in- dustry standards and associated tags. PARAMETERS Specifies a character string that contains two types of objects: Plain characters, which are copied to the output stream. Conversion specifi- cations, each of which causes zero or more items to be fetched from the stdarg parameter lists. Specifies the arguments to be printed. Speci- fies the output stream. Specifies the buffer to which output is printed. DESCRIPTION The vprintf(), vfprintf(), and vsprintf() functions format and write stdarg parameter lists. These functions are the same as the printf(), fprintf(), and sprintf() functions, respectively, except that these functions are not called with a variable number of parameters. Instead, vprintf(), vfprintf(), and vsprintf() are called with a parameter list pointer as defined by stdarg. Because these functions invoke the va_arg() macro and not the va_end() macro, the value of printarg is indeterminate after a return. Therefore, applications should execute a call to the va_end() macro af- ter a call to one of these functions. EXAMPLES The following example demonstrates how the vfprintf() function can be used to write an error routine: #include <stdarg.h> #include <stdio.h> void error(char *funct, char *fmt, ...) { va_list args; /* ** Display the name of the function that called error */ fprintf(stderr, "ERROR in %s: ", funct); /* ** Display the remainder of the message */ va_start(args, fmt); vfprintf(stderr, fmt, args); va_end(args); abort(); } RELATED INFORMATION Functions: fopen(3), printf(3), vwprintf(3), wprintf(3) delim off vprintf(3)