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Update port mode bits documentation.

* libguile/ports.h: Update documentation of port mode bits.
This commit is contained in:
Andy Wingo 2016-05-14 23:25:39 +02:00
parent 9ecf77a82d
commit a9d0fe9ea1

View file

@ -48,16 +48,15 @@ SCM_INTERNAL SCM scm_i_port_weak_set;
#define SCM_EOF_OBJECT_P(x) (scm_is_eq ((x), SCM_EOF_VAL))
/* PORT FLAGS
* A set of flags characterizes a port.
* Note that we reserve the bits 1 << 24 and above for use by the
* routines in the port's scm_ptobfuns structure.
*/
#define SCM_OPN (1L<<16) /* Is the port open? */
#define SCM_RDNG (2L<<16) /* Is it a readable port? */
#define SCM_WRTNG (4L<<16) /* Is it writable? */
#define SCM_BUF0 (8L<<16) /* Is it unbuffered? */
#define SCM_BUFLINE (64L<<16) /* Is it line-buffered? */
/* A port's first word contains its tag, which is a tc7 value. Above
there is a flag indicating whether the port is open or not, and then
some "mode bits": flags indicating whether the port is an input
and/or an output port and how Guile should buffer the port. */
#define SCM_OPN (1U<<16) /* Is the port open? */
#define SCM_RDNG (1U<<17) /* Is it a readable port? */
#define SCM_WRTNG (1U<<18) /* Is it writable? */
#define SCM_BUF0 (1U<<19) /* Is it unbuffered? */
#define SCM_BUFLINE (1U<<20) /* Is it line-buffered? */
#define SCM_PORTP(x) (SCM_HAS_TYP7 (x, scm_tc7_port))
#define SCM_OPPORTP(x) (SCM_PORTP (x) && (SCM_CELL_WORD_0 (x) & SCM_OPN))