stfd.3

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3 代码 · 共 210 行

.TH stfd 3 RISC
.SH Name
stfd, st_currentifd, st_ifdmax, st_setfd, st_fdadd, st_symadd, st_auxadd, st_stradd, st_lineadd, st_pdadd, st_ifd_pcfd, st_pcfd_ifd, st_psym_ifd_isym, st_paux_ifd_iaux, st_paux_iaux, st_str_iss, st_str_ifd_iss, st_ppd_ifd_isym, st_malloc  \- routines that provide 
access to per file descriptor section of the
symbol table
.SH Syntax
.nf
.B #include <syms.h>
.PP
.ft B
long st_currentifd ()
.PP
.ft B
long st_ifdmax ()
.PP
.ft B
void st_setfd (ifd)
long ifd;
.PP
.ft B
long st_fdadd (filename)
char *filename;
.PP
.ft B
long st_symadd (iss, value, st, sc, freloc, index)
long iss;
long value;
long st;
long sc;
long freloc;
long index;
.PP
.ft B
long st_auxadd (aux)
AUXU aux;
.PP
.ft B
long st_stradd (cp)
char *cp;
.PP
.ft B
long st_lineadd (line)
long line;
.PP
.ft B
long st_pdadd (isym)
long isym;
.PP
.ft B
long st_ifd_pcfd (pcfd1)
pCFDR pcfd1;
.PP
.ft B
pCFDR st_pcfd_ifd (ifd)
long ifd;
.PP
.ft B
pSYMR st_psym_ifd_isym (ifd, isym)
long ifd;
long isym;
.PP
.ft B
pAUXU st_paux_ifd_iaux (ifd, iaux)
long ifd;
long iaux;
.PP
.ft B
pAUXU st_paux_iaux (iaux)
long iaux;
.PP
.ft B
char *st_str_iss (iss)
long iss;
.PP
.ft B
char *st_str_ifd_iss (ifd, iss)
long ifd;
long iss;
.PP
.ft B
pPDR st_ppd_ifd_isym (ifd, isym)
long ifd;
long isym;
.PP
.ft B
char * st_malloc (ptr,psize,itemsize,baseitems)
char *ptr;
long *size;
long itemsize;
long baseitems;
.PP
.ft B
.fi
.ft R
.br
.SH Description
The
.B stfd
routines provide an interface to objects handled on a per file
descriptor (or fd) level.  For example: local symbols, 
auxiliaries, local strings, line numbers, optimization
entries, procedure descriptor entries, and the file descriptors.
These routines constitute a group because they deal with
objects corresponding to fields in the
.I FDR
structure.
.PP
A fd can be activated by reading an existing one into memory or by
creating a new one.
The compilation unit routines
.I st_readbinary
and
.I st_readst
read file descriptors and their constituent parts
into memory from a symbol table on disk.
.PP
The
.I st_fdadd
adds a file descriptor to the list of file descriptors. The 
.I lang
field is initialized from a user specified global 
.I st_lang 
that should be set to a constant designated for the language in 
.I symconst.h. 
The
.I fMerge
field is initialized from the user specified global st_merge that specifies
whether the file is to start with the attribute of being able
to be merged with identical files at load time. The
.I fBigendian
field is initialized by the 
.MS gethostsex 3  
routine, which determines the
permanent byte ordering for the auxiliary and line number entries 
for this file.
.PP
The
.I st_fdadd 
adds the null string to the new files string table that is
accessible by the constant issNull (0.  It also adds the filename to the
string table and sets the
.I rss
field. Finally, the current file is set to the newly added file so that
later calls operate on that file.
.PP
All routines for fd-level objects handle only the current file
unless a file index is specified. The current file can also be set with
.I st_setfd.
.PP
Programs can find the current file by calling
.I st_currentifd,
which returns the current index. Programs can find the number of
files by calling
.I st_ifdmax.
The fd routines only require working with indices to do most things.
They allow more in-depth manipulation by allowing users to get the
compile time file descriptor
.I (CFDR
see 
.I stsupport.h) 
that contains memory pointers to the per file tables (rather
than indices or offsets used in disk files). 
Users can retrieve a pointer to the CFDR by calling
.I st_pcfd_ifd
with the index to the desired file. The inverse mapping
.I st_ifd_pcfd
exists, as well. 
.PP
Each of fd's constituent parts has an add routine:
.I st_symadd,
.I st_stradd,
.I st_lineadd,
.I st_pdadd,
and
.I st_auxadd. 
The parameters of the add routines correspond to the fields of the
added object (see \fIsym.h\fR). The \fIpdadd\fR routine lets users fill in
the isym field only. Further information can be added by directly accessing
the procedure descriptor entry. 
.PP
The add routines return an index that can
be used to retrieve a pointer to part of
the desired object with one of the following
routines:
.I st_psym_isym,
.I st_str_iss,
and
.I st_paux_iaux.
.NT
These routines only return objects within the current 
file. The following
routines allow for file specification:
.I st_psym_ifd_isym,
.I st_aux_ifd_iaux,
and
.I st_str_ifd_iss.
.NE
The
.I st_ppd_ifd_isym 
allows access to procedures through
the file index for the file where they occur
and the isym field of the entry that points at the local symbol for
that procedure. 
.PP
The return index from st_symadd should be used to get a dense number
(see stcu).  That number should be the ucode block number for the object the
symbol describes.
.SH See Also
stcu(3), stfe(3), sym.h(5), stsupport.h(5)