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@(#)stdio.3 6.2 (Berkeley) 05/13/86
FILE *stdin;
FILE *stdout;
FILE *stderr;
A file with associated buffering is called a stream , and is declared to be a pointer to a defined type FILE . Fopen (3S) creates certain descriptive data for a stream and returns a pointer to designate the stream in all further transactions. There are three normally open streams with constant pointers declared in the include file and associated with the standard open files:
10n stdin standard input file
.ns
stdout standard output file
.ns
stderr standard error file
A constant `pointer' NULL (0) designates no stream at all.
An integer constant EOF (-1) is returned upon end of file or error by integer functions that deal with streams.
Any routine that uses the standard input/output package must include the header file < stdio.h > of pertinent macro definitions. The functions and constants mentioned in sections labeled 3S are declared in the include file and need no further declaration. The constants, and the following `functions' are implemented as macros; redeclaration of these names is perilous: getc , getchar , putc , putchar , feof , ferror , fileno .
For purposes of efficiency, this implementation of the standard library has been changed to line buffer output to a terminal by default and attempts to do this transparently by flushing the output whenever a read (2) from the standard input is necessary. This is almost always transparent, but may cause confusion or malfunctioning of programs which use standard i/o routines but use read (2) themselves to read from the standard input.
In cases where a large amount of computation is done after printing part of a line on an output terminal, it is necessary to fflush (3S) the standard output before going off and computing so that the output will appear.
Name Appears on Page Description clearerr ferror.3s stream status inquiries fclose fclose.3s close or flush a stream fdopen fopen.3s open a stream feof ferror.3s stream status inquiries ferror ferror.3s stream status inquiries fflush fclose.3s close or flush a stream fgetc getc.3s get character or word from stream fgets gets.3s get a string from a stream fileno ferror.3s stream status inquiries fopen fopen.3s open a stream fprintf printf.3s formatted output conversion fputc putc.3s put character or word on a stream fputs puts.3s put a string on a stream fread fread.3s buffered binary input/output freopen fopen.3s open a stream fscanf scanf.3s formatted input conversion fseek fseek.3s reposition a stream ftell fseek.3s reposition a stream fwrite fread.3s buffered binary input/output getc getc.3s get character or word from stream getchar getc.3s get character or word from stream gets gets.3s get a string from a stream getw getc.3s get character or word from stream printf printf.3s formatted output conversion putc putc.3s put character or word on a stream putchar putc.3s put character or word on a stream puts puts.3s put a string on a stream putw putc.3s put character or word on a stream rewind fseek.3s reposition a stream scanf scanf.3s formatted input conversion setbuf setbuf.3s assign buffering to a stream setbuffer setbuf.3s assign buffering to a stream setlinebuf setbuf.3s assign buffering to a stream sprintf printf.3s formatted output conversion sscanf scanf.3s formatted input conversion ungetc ungetc.3s push character back into input stream