Description:
This routine opens the
named GSD file and reads its contents into memory. It returns a standard C file descriptor, a GSD file
descriptor, a pointer to the array of GSD item descriptors, and a pointer to the collective
data.
This routine allocates memory to accommodate the GSD file descriptor, the GSD item descriptors, and
the data from the GSD file. It also leaves the GSD file open. Any call to this routine must be matched
with a call to gsdClose with the information returned by this routine. gsdClose will close the file
and release the memory allocated by this routine.
Invocation
int gsdOpenRead( char
file, float
version, char
label, int
no_items, FILE
fptr,
void file_dsc,
void item_dsc,
char data_ptr
);
Arguments
char file
(Given)
The name of the GSD file to be opened.
float
version (Returned)
The GSD
file version number.
char label
(Returned)
The GSD file label. This is a null-terminated string. It should be declared by the calling routine with length
41.
int no_items
(Returned)
The number of items in the GSD file.
FILE
fptr
(Returned)
The file descriptor for the GSD file opened.
void
file_dsc
(Returned)
The GSD file descriptor. This routine allocates the memory necessary and fills it with the relevant
information from the GSD file. A call to gsdClose will release this memory (given the pointer).
void
item_dsc
(Returned)
The array of GSD item descriptors. This routine allocates the memory necessary and
fills it with the relevant information from the GSD file. A call to gsdClose will release this
memory (given the pointer). The number of array elements is returned in no_items.
char
data_ptr
(Returned)
The buffer with all the data from the GSD file. This routine allocates the memory
necessary and reads the data into it. A call to gsdClose will release this memory (given
the pointer). The size of this buffer does not matter, but it can be calculated in bytes as
file_dsc-end_data
- file_dsc-str_data
1 if you
know what a struct file_descriptor looks like.
Returned Value
int gsdOpenRead();
Status. Status is
set to
-
[1:] Failure to open named file,
-
[2:] Failure to read file_dsc from file,
-
[3:] Failure to allocate memory for item_dsc,
-
[4:] Failure to read item_dsc from file,
-
[6:] Failure to read data_ptr from file,
-
[7:] Failure to allocate memory for data_ptr,
-
[0:] Otherwise.
Prototype
available via #include "gsd.h"
Copyright
Copyright
(C) 1986-1999 Particle Physics and Astronomy Research Council. All Rights Reserved.