BIO_S_FD(3) BSD Library Functions Manual BIO_S_FD(3)NAME
BIO_s_fd, BIO_set_fd, BIO_get_fd, BIO_new_fd — file descriptor BIO
SYNOPSIS
#include <openssl/bio.h>
BIO_METHOD *
BIO_s_fd(void);
#define BIO_set_fd(b,fd,c) BIO_int_ctrl(b,BIO_C_SET_FD,c,fd)
#define BIO_get_fd(b,c) BIO_ctrl(b,BIO_C_GET_FD,0,(char *)c)
BIO *
BIO_new_fd(int fd, int close_flag);
DESCRIPTIONBIO_s_fd() returns the file descriptor BIO method. This is a wrapper
around the platform's file descriptor routines such as read(2) and
write(2).
BIO_read(3) and BIO_write(3) read or write the underlying descriptor.
BIO_puts(3) is supported but BIO_gets(3) is not.
If the close flag is set, close(2) is called on the underlying file
descriptor when the BIO is freed.
BIO_reset(3) attempts to set the file pointer to the start of the file
using lseek(fd, 0, 0).
BIO_seek(3) sets the file pointer to position ofs from start of file
using lseek(fd, ofs, 0).
BIO_tell(3) returns the current file position by calling lseek(fd, 0, 1).
BIO_set_fd() sets the file descriptor of BIO b to fd and the close flag
to c.
BIO_get_fd() places the file descriptor in c if it is not NULL, it also
returns the file descriptor. If c is not NULL, it should be of type int
*.
BIO_new_fd() returns a file descriptor BIO using fd and close_flag.
NOTES
The behaviour of BIO_read(3) and BIO_write(3) depends on the behavior of
the platform's read(2) and write(2) 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 BIO_read(3) and BIO_should_retry(3)
manual pages.
File descriptor BIOs should not be used for socket I/O. Use socket BIOs
instead.
RETURN VALUESBIO_s_fd() returns the file descriptor BIO method.
BIO_reset(3) returns zero for success and -1 if an error occurred.
BIO_seek(3) and BIO_tell(3) return the current file position or -1 if an
error occurred. These values reflect the underlying lseek(2) behaviour.
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 if an error
occurred.
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);
SEE ALSOBIO_read(3), BIO_seek(3)BSD April 20, 2024 BSD
