diff options
Diffstat (limited to 'src/include/storage/fd.h')
| -rw-r--r-- | src/include/storage/fd.h | 48 |
1 files changed, 37 insertions, 11 deletions
diff --git a/src/include/storage/fd.h b/src/include/storage/fd.h index 69f7ba62b90..a867775743c 100644 --- a/src/include/storage/fd.h +++ b/src/include/storage/fd.h @@ -6,7 +6,7 @@ * * Copyright (c) 1994, Regents of the University of California * - * $Id: fd.h,v 1.12 1999/02/13 23:22:05 momjian Exp $ + * $Id: fd.h,v 1.13 1999/05/09 00:52:06 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -17,19 +17,23 @@ * {File Name Open, Allocate, Free} File * * These are NOT JUST RENAMINGS OF THE UNIX ROUTINES. - * use them for all file activity... + * Use them for all file activity... * - * fd = FilePathOpenFile("foo", O_RDONLY); * File fd; - * - * use AllocateFile if you need a file descriptor in some other context. - * it will make sure that there is a file descriptor free - * - * use FreeFile to let the virtual file descriptor package know that - * there is now a free fd (when you are done with it) + * fd = FilePathOpenFile("foo", O_RDONLY); * * AllocateFile(); * FreeFile(); + * + * Use AllocateFile, not fopen, if you need a stdio file (FILE*); then + * use FreeFile, not fclose, to close it. AVOID using stdio for files + * that you intend to hold open for any length of time, since there is + * no way for them to share kernel file descriptors with other files. + * + * The BufFile routines provide a partial replacement for stdio. Currently + * they only support buffered access to a virtual file, without any of + * stdio's formatting features. That's enough for immediate needs, but + * the set of facilities could be expanded if necessary. */ #ifndef FD_H #define FD_H @@ -44,7 +48,11 @@ typedef char *FileName; typedef int File; -/* originally in libpq-fs.h */ +/* BufFile is an opaque type whose details are not known outside fd.c. */ + +typedef struct BufFile BufFile; + +/* why is this here? fd.c doesn't want it ... */ struct pgstat { /* just the fields we need from stat * structure */ @@ -62,8 +70,11 @@ struct pgstat /* * prototypes for functions in fd.c */ + +/* Operations on virtual Files --- equivalent to Unix kernel file ops */ extern File FileNameOpenFile(FileName fileName, int fileFlags, int fileMode); extern File PathNameOpenFile(FileName fileName, int fileFlags, int fileMode); +extern File OpenTemporaryFile(void); extern void FileClose(File file); extern void FileUnlink(File file); extern int FileRead(File file, char *buffer, int amount); @@ -71,10 +82,25 @@ extern int FileWrite(File file, char *buffer, int amount); extern long FileSeek(File file, long offset, int whence); extern int FileTruncate(File file, int offset); extern int FileSync(File file); -extern int FileNameUnlink(char *filename); + +/* Operations that allow use of regular stdio --- USE WITH CAUTION */ extern FILE *AllocateFile(char *name, char *mode); extern void FreeFile(FILE *); + +/* Operations on BufFiles --- a very incomplete emulation of stdio + * atop virtual Files... + */ +extern BufFile *BufFileCreate(File file); +extern void BufFileClose(BufFile *file); +extern size_t BufFileRead(BufFile *file, void *ptr, size_t size); +extern size_t BufFileWrite(BufFile *file, void *ptr, size_t size); +extern int BufFileFlush(BufFile *file); +extern long BufFileSeek(BufFile *file, long offset, int whence); + +/* Miscellaneous support routines */ +extern int FileNameUnlink(char *filename); extern void closeAllVfds(void); +extern void AtEOXact_Files(void); extern int pg_fsync(int fd); #endif /* FD_H */ |