FOPEN(3S) FOPEN(3S) NAME fopen, freopen, fdopen - open a stream SYNOPSIS #include <stdio.h> FILE *fopen(filename, type) char *filename, *type; FILE *freopen(filename, type, stream) char *filename, *type; FILE *stream; FILE *fdopen(fildes, type) char *type; DESCRIPTION Fopen opens the file named by filename and associates a stream with it. Fopen returns a pointer to be used to iden- tify the stream in subsequent operations. Type is a character string having one of the following val- ues: "r" open for reading "w" create for writing "a" append: open for writing at end of file, or create for writing Freopen substitutes the named file in place of the open stream. It returns the original value of stream. The origi- nal stream is closed. Freopen is typically used to attach the preopened constant names, `stdin', `stdout', `stderr', to specified files. Fdopen associates a stream with a file descriptor obtained from open, dup, creat, or pipe(2). The type of the stream must agree with the mode of the open file. SEE ALSO open(2), fclose(3) DIAGNOSTICS Fopen and freopen return the pointer NULL if filename cannot be accessed. BUGS Fdopen is not portable to systems other than UNIX.