SCGETSCANENT(3) Impressario SCGETSCANENT(3)NAME
SCSetScanEnt, SCGetScanEnt, SCEndScanEnt - Getting information about
installed scanners
SYNOPSIS
#include <stdio.h>
#include <scanner.h>
FILE *SCSetScanEnt(void);
SCANENT *SCGetScanEnt(FILE *fp);
int SCEndScanEnt(FILE *fp);
DESCRIPTION
These routines provide a programmatic interface for reading the file
/usr/lib/scan/scanners, which contains a one line entry specifying the
name, driver, device, and options program for each scanner installed on
the system.
SCSetScanEnt opens /usr/lib/scan/scanners, returning a pointer to a FILE
structure. SCGetScanEnt parses the next line of fp into a SCANENT
structure, which is declared in <scanner.h> as follows:
typedef struct tag_scanent {
char *name;
char *driver;
char *device;
char *options;
} SCANENT;
In this structure, name is the name of the scanner assigned by the system
administrator using scanners(1M) at the time the scanner was installed.
driver is the name of the scanner driver for this scanner. device is the
device parameter passed to the driver, and options is the scanner
specific options program for this scanner.
From a scanner application's point of view, name is the only significant
field. name is the string to be passed to SCOpen(3) to open a scanner.
RETURN VALUE
SCSetScanEnt returns a pointer to a FILE structure if successful, or NULL
if an error occurs.
SCGetScanEnt returns a pointer to a SCANENT structure, or NULL if there
are no more scanners left to parse in /usr/lib/scan/scanners.
SCEndScanEnt returns 0 if successful, -1 if error.
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SCGETSCANENT(3) Impressario SCGETSCANENT(3)
In the event of an error, SCSetScanEnt and SCEndScanEnt will set SCerrno
to indicate the cause of the error.
EXECUTION ERROR CODES
SCENOSCANNERS No scanners are installed
In addition, these functions may fail as the result of a failed system
call, in which case SCerrno will be set to a value from
/usr/include/sys/errno.h.
EXAMPLE
The following example prints out the names of all installed scanners. A
scanner application can use these functions to present a list of
installed scanners to the user, so the user can select which one to open.
#include <stdio.h>
#include <scanner.h>
int
main(void)
{
FILE *fp;
SCANENT *ent;
if ((fp = SCSetScanEnt()) == NULL) {
SCPerror("SCSetScanEnt");
exit(1);
}
printf("Installed scanners:\n");
while ((ent = SCGetScanEnt(fp)) != NULL) {
printf("%s\n", ent->name);
}
SCEndScanEnt(fp);
exit(0);
}
WARNING
The return value of SCGetScanEnt points to memory owned by libscan(3).
The calling program should not modify the memory pointed to by the return
value of SCGetScanEnt, nor should any assumptions be made about its value
after subsequent calls to SCGetScanEnt. Any needed information should be
copied into program memory before calling SCGetScanEnt again.
SEE ALSOlibscan(3), SCOpen(3), scanners(1M).
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