#include <lcio.h> size_t afwriteh(const void *ptr, size_t size, size_t count, FILE *f);
afwriteh
writes items to the stream associated with the FILE
object that f
addresses. size
defines the size of each item,
count
defines the number of items to be written, and ptr
addresses the area containing the items. If all the items do not fit into
the current record, a diagnostic message is generated and the file's error
flag is set.
Calls to afwriteh
to write items of type typeval
commonly have
this form:
typeval buf[count]; afwriteh(buf, sizeof(typeval), count, f);
You can only use afwriteh
with a binary stream. See
Augmented Standard I/O for more information.
afwriteh
returns the number of items written. If there are too many
items, only those that fit are written.
afwriteh
behaves exactly
like fwrite
because such a file is processed as a continuous stream of
characters without record boundaries. To process a file with relative
attributes on a record-by-record basis, you must open it with afopen
and specify the "seq"
access method.
afwriteh
never writes more than a single record; an error occurs if
there is no room in the current record for all items.
The return value from afwriteh
does not indicate whether the call is
completely successful. You can use the ferror
function to determine
whether an error occurs.
afreadh
example:
#include <lcio.h> #include <stdlib.h> #define NAMESIZE 30 #define ADDRSIZE 80 main() { FILE *custf; struct hdr { int custno; char type; }; struct custrec { char name[NAMESIZE]; char addr[ADDRSIZE]; }; typedef double payrec; int customers[] = { 1001, 1002, 1003, 1004}; struct custrec custinfo[] = { { "Paul Barnes", "256 Oak Street, Cary, NC" }, { "Janice Palmer", "1500 Pine Avenue, Austin, TX" }, { "Frank Smith", "92 Maple Boulevard, Concord, NH" }, { "Carlotta Perez", "634 First Street, Los Angeles, CA" } }; payrec payment[] = { 54.40, 234, 16.81, 523}; struct hdr cust_hdr; int i; custf = fopen("tso:custfile", "wb"); if (!custf) exit(1); /* Write out one customer record and one payment record */ /* for each customer. */ for (i = 0; i < sizeof(customers)/sizeof(customers[0]); ++i){ cust_hdr.custno = customers[i]; cust_hdr.type = 'C'; afwriteh(&cust_hdr, sizeof(cust_hdr), 1, custf); if (ferror(custf)) exit(1); afwrite(&custinfo[i], sizeof(struct custrec), 1, custf); if (ferror(custf)) exit(1); cust_hdr.type = 'P'; afwriteh(&cust_hdr, sizeof(cust_hdr), 1, custf); if (ferror(custf)) exit(1); afwrite(&payment[i], sizeof(payrec), 1, custf); if (ferror(custf)) exit(1); } fclose(custf); printf("%d customer records and %d payment records written.n", sizeof(customers)/sizeof(customers[0]), sizeof(customers)/sizeof(customers[0])); exit(0); }
afwrite
Copyright (c) 1998 SAS Institute Inc. Cary, NC, USA. All rights reserved.