=pod =head1 NAME BIO_s_fd, BIO_set_fd, BIO_get_fd, BIO_new_fd - file descriptor BIO =head1 SYNOPSIS #include const BIO_METHOD *BIO_s_fd(void); int BIO_set_fd(BIO *b, int fd, int c); int BIO_get_fd(BIO *b, int *c); BIO *BIO_new_fd(int fd, int close_flag); =head1 DESCRIPTION BIO_s_fd() returns the file descriptor BIO method. This is a wrapper round the platforms file descriptor routines such as read() and write(). BIO_read_ex() and BIO_write_ex() read or write the underlying descriptor. BIO_puts() is supported but BIO_gets() is not. If the close flag is set then close() is called on the underlying file descriptor when the BIO is freed. BIO_reset() attempts to change the file pointer to the start of file such as by using B. BIO_seek() sets the file pointer to position B from start of file such as by using B. BIO_tell() returns the current file position such as by calling B. BIO_set_fd() sets the file descriptor of BIO B to B and the close flag to B. BIO_get_fd() places the file descriptor in B if it is not NULL, it also returns the file descriptor. BIO_new_fd() returns a file descriptor BIO using B and B. =head1 NOTES The behaviour of BIO_read_ex() and BIO_write_ex() depends on the behavior of the platforms read() and write() calls on the descriptor. If the underlying file descriptor is in a non blocking mode then the BIO will behave in the manner described in the L and L manual pages. File descriptor BIOs should not be used for socket I/O. Use socket BIOs instead. BIO_set_fd() and BIO_get_fd() are implemented as macros. =head1 RETURN VALUES BIO_s_fd() returns the file descriptor BIO method. BIO_set_fd() always returns 1. BIO_get_fd() returns the file descriptor or -1 if the BIO has not been initialized. BIO_new_fd() returns the newly allocated BIO or NULL is an error occurred. =head1 EXAMPLE This is a file descriptor BIO version of "Hello World": BIO *out; out = BIO_new_fd(fileno(stdout), BIO_NOCLOSE); BIO_printf(out, "Hello World\n"); BIO_free(out); =head1 SEE ALSO L, L, L, L, L, L, L, L, L, L =head1 COPYRIGHT Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at L. =cut